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PK ! sӢ Ӣ ddl.pynu [ # sql/ddl.py
# Copyright (C) 2009-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
Provides the hierarchy of DDL-defining schema items as well as routines
to invoke them for a create/drop call.
"""
from .base import _bind_or_error
from .base import _generative
from .base import Executable
from .base import SchemaVisitor
from .elements import ClauseElement
from .. import event
from .. import exc
from .. import util
from ..util import topological
class _DDLCompiles(ClauseElement):
def _compiler(self, dialect, **kw):
"""Return a compiler appropriate for this ClauseElement, given a
Dialect."""
return dialect.ddl_compiler(dialect, self, **kw)
class DDLElement(Executable, _DDLCompiles):
"""Base class for DDL expression constructs.
This class is the base for the general purpose :class:`.DDL` class,
as well as the various create/drop clause constructs such as
:class:`.CreateTable`, :class:`.DropTable`, :class:`.AddConstraint`,
etc.
:class:`.DDLElement` integrates closely with SQLAlchemy events,
introduced in :ref:`event_toplevel`. An instance of one is
itself an event receiving callable::
event.listen(
users,
'after_create',
AddConstraint(constraint).execute_if(dialect='postgresql')
)
.. seealso::
:class:`.DDL`
:class:`.DDLEvents`
:ref:`event_toplevel`
:ref:`schema_ddl_sequences`
"""
_execution_options = Executable._execution_options.union(
{"autocommit": True}
)
target = None
on = None
dialect = None
callable_ = None
def _execute_on_connection(self, connection, multiparams, params):
return connection._execute_ddl(self, multiparams, params)
def execute(self, bind=None, target=None):
"""Execute this DDL immediately.
Executes the DDL statement in isolation using the supplied
:class:`.Connectable` or
:class:`.Connectable` assigned to the ``.bind``
property, if not supplied. If the DDL has a conditional ``on``
criteria, it will be invoked with None as the event.
:param bind:
Optional, an ``Engine`` or ``Connection``. If not supplied, a valid
:class:`.Connectable` must be present in the
``.bind`` property.
:param target:
Optional, defaults to None. The target :class:`_schema.SchemaItem`
for the execute call. Will be passed to the ``on`` callable if any,
and may also provide string expansion data for the statement.
See ``execute_at`` for more information.
"""
if bind is None:
bind = _bind_or_error(self)
if self._should_execute(target, bind):
return bind.execute(self.against(target))
else:
bind.engine.logger.info("DDL execution skipped, criteria not met.")
@util.deprecated(
"0.7",
"The :meth:`.DDLElement.execute_at` method is deprecated and will "
"be removed in a future release. Please use the :class:`.DDLEvents` "
"listener interface in conjunction with the "
":meth:`.DDLElement.execute_if` method.",
)
def execute_at(self, event_name, target):
"""Link execution of this DDL to the DDL lifecycle of a SchemaItem.
Links this ``DDLElement`` to a ``Table`` or ``MetaData`` instance,
executing it when that schema item is created or dropped. The DDL
statement will be executed using the same Connection and transactional
context as the Table create/drop itself. The ``.bind`` property of
this statement is ignored.
:param event:
One of the events defined in the schema item's ``.ddl_events``;
e.g. 'before-create', 'after-create', 'before-drop' or 'after-drop'
:param target:
The Table or MetaData instance for which this DDLElement will
be associated with.
A DDLElement instance can be linked to any number of schema items.
``execute_at`` builds on the ``append_ddl_listener`` interface of
:class:`_schema.MetaData` and :class:`_schema.Table` objects.
Caveat: Creating or dropping a Table in isolation will also trigger
any DDL set to ``execute_at`` that Table's MetaData. This may change
in a future release.
"""
def call_event(target, connection, **kw):
if self._should_execute_deprecated(
event_name, target, connection, **kw
):
return connection.execute(self.against(target))
event.listen(target, "" + event_name.replace("-", "_"), call_event)
@_generative
def against(self, target):
"""Return a copy of this DDL against a specific schema item."""
self.target = target
@_generative
def execute_if(self, dialect=None, callable_=None, state=None):
r"""Return a callable that will execute this
DDLElement conditionally.
Used to provide a wrapper for event listening::
event.listen(
metadata,
'before_create',
DDL("my_ddl").execute_if(dialect='postgresql')
)
:param dialect: May be a string, tuple or a callable
predicate. If a string, it will be compared to the name of the
executing database dialect::
DDL('something').execute_if(dialect='postgresql')
If a tuple, specifies multiple dialect names::
DDL('something').execute_if(dialect=('postgresql', 'mysql'))
:param callable\_: A callable, which will be invoked with
four positional arguments as well as optional keyword
arguments:
:ddl:
This DDL element.
:target:
The :class:`_schema.Table` or :class:`_schema.MetaData`
object which is the
target of this event. May be None if the DDL is executed
explicitly.
:bind:
The :class:`_engine.Connection` being used for DDL execution
:tables:
Optional keyword argument - a list of Table objects which are to
be created/ dropped within a MetaData.create_all() or drop_all()
method call.
:state:
Optional keyword argument - will be the ``state`` argument
passed to this function.
:checkfirst:
Keyword argument, will be True if the 'checkfirst' flag was
set during the call to ``create()``, ``create_all()``,
``drop()``, ``drop_all()``.
If the callable returns a True value, the DDL statement will be
executed.
:param state: any value which will be passed to the callable\_
as the ``state`` keyword argument.
.. seealso::
:class:`.DDLEvents`
:ref:`event_toplevel`
"""
self.dialect = dialect
self.callable_ = callable_
self.state = state
def _should_execute(self, target, bind, **kw):
if self.on is not None and not self._should_execute_deprecated(
None, target, bind, **kw
):
return False
if isinstance(self.dialect, util.string_types):
if self.dialect != bind.engine.name:
return False
elif isinstance(self.dialect, (tuple, list, set)):
if bind.engine.name not in self.dialect:
return False
if self.callable_ is not None and not self.callable_(
self, target, bind, state=self.state, **kw
):
return False
return True
def _should_execute_deprecated(self, event, target, bind, **kw):
if self.on is None:
return True
elif isinstance(self.on, util.string_types):
return self.on == bind.engine.name
elif isinstance(self.on, (tuple, list, set)):
return bind.engine.name in self.on
else:
return self.on(self, event, target, bind, **kw)
def __call__(self, target, bind, **kw):
"""Execute the DDL as a ddl_listener."""
if self._should_execute(target, bind, **kw):
return bind.execute(self.against(target))
def _check_ddl_on(self, on):
if on is not None and (
not isinstance(on, util.string_types + (tuple, list, set))
and not util.callable(on)
):
raise exc.ArgumentError(
"Expected the name of a database dialect, a tuple "
"of names, or a callable for "
"'on' criteria, got type '%s'." % type(on).__name__
)
def bind(self):
if self._bind:
return self._bind
def _set_bind(self, bind):
self._bind = bind
bind = property(bind, _set_bind)
def _generate(self):
s = self.__class__.__new__(self.__class__)
s.__dict__ = self.__dict__.copy()
return s
class DDL(DDLElement):
"""A literal DDL statement.
Specifies literal SQL DDL to be executed by the database. DDL objects
function as DDL event listeners, and can be subscribed to those events
listed in :class:`.DDLEvents`, using either :class:`_schema.Table` or
:class:`_schema.MetaData` objects as targets.
Basic templating support allows
a single DDL instance to handle repetitive tasks for multiple tables.
Examples::
from sqlalchemy import event, DDL
tbl = Table('users', metadata, Column('uid', Integer))
event.listen(tbl, 'before_create', DDL('DROP TRIGGER users_trigger'))
spow = DDL('ALTER TABLE %(table)s SET secretpowers TRUE')
event.listen(tbl, 'after_create', spow.execute_if(dialect='somedb'))
drop_spow = DDL('ALTER TABLE users SET secretpowers FALSE')
connection.execute(drop_spow)
When operating on Table events, the following ``statement``
string substitutions are available::
%(table)s - the Table name, with any required quoting applied
%(schema)s - the schema name, with any required quoting applied
%(fullname)s - the Table name including schema, quoted if needed
The DDL's "context", if any, will be combined with the standard
substitutions noted above. Keys present in the context will override
the standard substitutions.
"""
__visit_name__ = "ddl"
@util.deprecated_params(
on=(
"0.7",
"The :paramref:`.DDL.on` parameter is deprecated and will be "
"removed in a future release. Please refer to "
":meth:`.DDLElement.execute_if`.",
)
)
def __init__(self, statement, on=None, context=None, bind=None):
"""Create a DDL statement.
:param statement:
A string or unicode string to be executed. Statements will be
processed with Python's string formatting operator. See the
``context`` argument and the ``execute_at`` method.
A literal '%' in a statement must be escaped as '%%'.
SQL bind parameters are not available in DDL statements.
:param on:
Optional filtering criteria. May be a string, tuple or a callable
predicate. If a string, it will be compared to the name of the
executing database dialect::
DDL('something', on='postgresql')
If a tuple, specifies multiple dialect names::
DDL('something', on=('postgresql', 'mysql'))
If a callable, it will be invoked with four positional arguments
as well as optional keyword arguments:
:ddl:
This DDL element.
:event:
The name of the event that has triggered this DDL, such as
'after-create' Will be None if the DDL is executed explicitly.
:target:
The ``Table`` or ``MetaData`` object which is the target of
this event. May be None if the DDL is executed explicitly.
:connection:
The ``Connection`` being used for DDL execution
:tables:
Optional keyword argument - a list of Table objects which are to
be created/ dropped within a MetaData.create_all() or drop_all()
method call.
If the callable returns a true value, the DDL statement will be
executed.
:param context:
Optional dictionary, defaults to None. These values will be
available for use in string substitutions on the DDL statement.
:param bind:
Optional. A :class:`.Connectable`, used by
default when ``execute()`` is invoked without a bind argument.
.. seealso::
:class:`.DDLEvents`
:ref:`event_toplevel`
"""
if not isinstance(statement, util.string_types):
raise exc.ArgumentError(
"Expected a string or unicode SQL statement, got '%r'"
% statement
)
self.statement = statement
self.context = context or {}
self._check_ddl_on(on)
self.on = on
self._bind = bind
def __repr__(self):
return "<%s@%s; %s>" % (
type(self).__name__,
id(self),
", ".join(
[repr(self.statement)]
+ [
"%s=%r" % (key, getattr(self, key))
for key in ("on", "context")
if getattr(self, key)
]
),
)
class _CreateDropBase(DDLElement):
"""Base class for DDL constructs that represent CREATE and DROP or
equivalents.
The common theme of _CreateDropBase is a single
``element`` attribute which refers to the element
to be created or dropped.
"""
def __init__(self, element, on=None, bind=None):
self.element = element
self._check_ddl_on(on)
self.on = on
self.bind = bind
def _create_rule_disable(self, compiler):
"""Allow disable of _create_rule using a callable.
Pass to _create_rule using
util.portable_instancemethod(self._create_rule_disable)
to retain serializability.
"""
return False
class CreateSchema(_CreateDropBase):
"""Represent a CREATE SCHEMA statement.
The argument here is the string name of the schema.
"""
__visit_name__ = "create_schema"
def __init__(self, name, quote=None, **kw):
"""Create a new :class:`.CreateSchema` construct."""
self.quote = quote
super(CreateSchema, self).__init__(name, **kw)
class DropSchema(_CreateDropBase):
"""Represent a DROP SCHEMA statement.
The argument here is the string name of the schema.
"""
__visit_name__ = "drop_schema"
def __init__(self, name, quote=None, cascade=False, **kw):
"""Create a new :class:`.DropSchema` construct."""
self.quote = quote
self.cascade = cascade
super(DropSchema, self).__init__(name, **kw)
class CreateTable(_CreateDropBase):
"""Represent a CREATE TABLE statement."""
__visit_name__ = "create_table"
def __init__(
self, element, on=None, bind=None, include_foreign_key_constraints=None
):
"""Create a :class:`.CreateTable` construct.
:param element: a :class:`_schema.Table` that's the subject
of the CREATE
:param on: See the description for 'on' in :class:`.DDL`.
:param bind: See the description for 'bind' in :class:`.DDL`.
:param include_foreign_key_constraints: optional sequence of
:class:`_schema.ForeignKeyConstraint` objects that will be included
inline within the CREATE construct; if omitted, all foreign key
constraints that do not specify use_alter=True are included.
.. versionadded:: 1.0.0
"""
super(CreateTable, self).__init__(element, on=on, bind=bind)
self.columns = [CreateColumn(column) for column in element.columns]
self.include_foreign_key_constraints = include_foreign_key_constraints
class _DropView(_CreateDropBase):
"""Semi-public 'DROP VIEW' construct.
Used by the test suite for dialect-agnostic drops of views.
This object will eventually be part of a public "view" API.
"""
__visit_name__ = "drop_view"
class CreateColumn(_DDLCompiles):
"""Represent a :class:`_schema.Column`
as rendered in a CREATE TABLE statement,
via the :class:`.CreateTable` construct.
This is provided to support custom column DDL within the generation
of CREATE TABLE statements, by using the
compiler extension documented in :ref:`sqlalchemy.ext.compiler_toplevel`
to extend :class:`.CreateColumn`.
Typical integration is to examine the incoming :class:`_schema.Column`
object, and to redirect compilation if a particular flag or condition
is found::
from sqlalchemy import schema
from sqlalchemy.ext.compiler import compiles
@compiles(schema.CreateColumn)
def compile(element, compiler, **kw):
column = element.element
if "special" not in column.info:
return compiler.visit_create_column(element, **kw)
text = "%s SPECIAL DIRECTIVE %s" % (
column.name,
compiler.type_compiler.process(column.type)
)
default = compiler.get_column_default_string(column)
if default is not None:
text += " DEFAULT " + default
if not column.nullable:
text += " NOT NULL"
if column.constraints:
text += " ".join(
compiler.process(const)
for const in column.constraints)
return text
The above construct can be applied to a :class:`_schema.Table`
as follows::
from sqlalchemy import Table, Metadata, Column, Integer, String
from sqlalchemy import schema
metadata = MetaData()
table = Table('mytable', MetaData(),
Column('x', Integer, info={"special":True}, primary_key=True),
Column('y', String(50)),
Column('z', String(20), info={"special":True})
)
metadata.create_all(conn)
Above, the directives we've added to the :attr:`_schema.Column.info`
collection
will be detected by our custom compilation scheme::
CREATE TABLE mytable (
x SPECIAL DIRECTIVE INTEGER NOT NULL,
y VARCHAR(50),
z SPECIAL DIRECTIVE VARCHAR(20),
PRIMARY KEY (x)
)
The :class:`.CreateColumn` construct can also be used to skip certain
columns when producing a ``CREATE TABLE``. This is accomplished by
creating a compilation rule that conditionally returns ``None``.
This is essentially how to produce the same effect as using the
``system=True`` argument on :class:`_schema.Column`, which marks a column
as an implicitly-present "system" column.
For example, suppose we wish to produce a :class:`_schema.Table`
which skips
rendering of the PostgreSQL ``xmin`` column against the PostgreSQL
backend, but on other backends does render it, in anticipation of a
triggered rule. A conditional compilation rule could skip this name only
on PostgreSQL::
from sqlalchemy.schema import CreateColumn
@compiles(CreateColumn, "postgresql")
def skip_xmin(element, compiler, **kw):
if element.element.name == 'xmin':
return None
else:
return compiler.visit_create_column(element, **kw)
my_table = Table('mytable', metadata,
Column('id', Integer, primary_key=True),
Column('xmin', Integer)
)
Above, a :class:`.CreateTable` construct will generate a ``CREATE TABLE``
which only includes the ``id`` column in the string; the ``xmin`` column
will be omitted, but only against the PostgreSQL backend.
"""
__visit_name__ = "create_column"
def __init__(self, element):
self.element = element
class DropTable(_CreateDropBase):
"""Represent a DROP TABLE statement."""
__visit_name__ = "drop_table"
class CreateSequence(_CreateDropBase):
"""Represent a CREATE SEQUENCE statement."""
__visit_name__ = "create_sequence"
class DropSequence(_CreateDropBase):
"""Represent a DROP SEQUENCE statement."""
__visit_name__ = "drop_sequence"
class CreateIndex(_CreateDropBase):
"""Represent a CREATE INDEX statement."""
__visit_name__ = "create_index"
class DropIndex(_CreateDropBase):
"""Represent a DROP INDEX statement."""
__visit_name__ = "drop_index"
class AddConstraint(_CreateDropBase):
"""Represent an ALTER TABLE ADD CONSTRAINT statement."""
__visit_name__ = "add_constraint"
def __init__(self, element, *args, **kw):
super(AddConstraint, self).__init__(element, *args, **kw)
element._create_rule = util.portable_instancemethod(
self._create_rule_disable
)
class DropConstraint(_CreateDropBase):
"""Represent an ALTER TABLE DROP CONSTRAINT statement."""
__visit_name__ = "drop_constraint"
def __init__(self, element, cascade=False, **kw):
self.cascade = cascade
super(DropConstraint, self).__init__(element, **kw)
element._create_rule = util.portable_instancemethod(
self._create_rule_disable
)
class SetTableComment(_CreateDropBase):
"""Represent a COMMENT ON TABLE IS statement."""
__visit_name__ = "set_table_comment"
class DropTableComment(_CreateDropBase):
"""Represent a COMMENT ON TABLE '' statement.
Note this varies a lot across database backends.
"""
__visit_name__ = "drop_table_comment"
class SetColumnComment(_CreateDropBase):
"""Represent a COMMENT ON COLUMN IS statement."""
__visit_name__ = "set_column_comment"
class DropColumnComment(_CreateDropBase):
"""Represent a COMMENT ON COLUMN IS NULL statement."""
__visit_name__ = "drop_column_comment"
class DDLBase(SchemaVisitor):
def __init__(self, connection):
self.connection = connection
class SchemaGenerator(DDLBase):
def __init__(
self, dialect, connection, checkfirst=False, tables=None, **kwargs
):
super(SchemaGenerator, self).__init__(connection, **kwargs)
self.checkfirst = checkfirst
self.tables = tables
self.preparer = dialect.identifier_preparer
self.dialect = dialect
self.memo = {}
def _can_create_table(self, table):
self.dialect.validate_identifier(table.name)
effective_schema = self.connection.schema_for_object(table)
if effective_schema:
self.dialect.validate_identifier(effective_schema)
return not self.checkfirst or not self.dialect.has_table(
self.connection, table.name, schema=effective_schema
)
def _can_create_sequence(self, sequence):
effective_schema = self.connection.schema_for_object(sequence)
return self.dialect.supports_sequences and (
(not self.dialect.sequences_optional or not sequence.optional)
and (
not self.checkfirst
or not self.dialect.has_sequence(
self.connection, sequence.name, schema=effective_schema
)
)
)
def visit_metadata(self, metadata):
if self.tables is not None:
tables = self.tables
else:
tables = list(metadata.tables.values())
collection = sort_tables_and_constraints(
[t for t in tables if self._can_create_table(t)]
)
seq_coll = [
s
for s in metadata._sequences.values()
if s.column is None and self._can_create_sequence(s)
]
event_collection = [t for (t, fks) in collection if t is not None]
metadata.dispatch.before_create(
metadata,
self.connection,
tables=event_collection,
checkfirst=self.checkfirst,
_ddl_runner=self,
)
for seq in seq_coll:
self.traverse_single(seq, create_ok=True)
for table, fkcs in collection:
if table is not None:
self.traverse_single(
table,
create_ok=True,
include_foreign_key_constraints=fkcs,
_is_metadata_operation=True,
)
else:
for fkc in fkcs:
self.traverse_single(fkc)
metadata.dispatch.after_create(
metadata,
self.connection,
tables=event_collection,
checkfirst=self.checkfirst,
_ddl_runner=self,
)
def visit_table(
self,
table,
create_ok=False,
include_foreign_key_constraints=None,
_is_metadata_operation=False,
):
if not create_ok and not self._can_create_table(table):
return
table.dispatch.before_create(
table,
self.connection,
checkfirst=self.checkfirst,
_ddl_runner=self,
_is_metadata_operation=_is_metadata_operation,
)
for column in table.columns:
if column.default is not None:
self.traverse_single(column.default)
if not self.dialect.supports_alter:
# e.g., don't omit any foreign key constraints
include_foreign_key_constraints = None
self.connection.execute(
# fmt: off
CreateTable(
table,
include_foreign_key_constraints= # noqa
include_foreign_key_constraints, # noqa
)
# fmt: on
)
if hasattr(table, "indexes"):
for index in table.indexes:
self.traverse_single(index)
if self.dialect.supports_comments and not self.dialect.inline_comments:
if table.comment is not None:
self.connection.execute(SetTableComment(table))
for column in table.columns:
if column.comment is not None:
self.connection.execute(SetColumnComment(column))
table.dispatch.after_create(
table,
self.connection,
checkfirst=self.checkfirst,
_ddl_runner=self,
_is_metadata_operation=_is_metadata_operation,
)
def visit_foreign_key_constraint(self, constraint):
if not self.dialect.supports_alter:
return
self.connection.execute(AddConstraint(constraint))
def visit_sequence(self, sequence, create_ok=False):
if not create_ok and not self._can_create_sequence(sequence):
return
self.connection.execute(CreateSequence(sequence))
def visit_index(self, index):
self.connection.execute(CreateIndex(index))
class SchemaDropper(DDLBase):
def __init__(
self, dialect, connection, checkfirst=False, tables=None, **kwargs
):
super(SchemaDropper, self).__init__(connection, **kwargs)
self.checkfirst = checkfirst
self.tables = tables
self.preparer = dialect.identifier_preparer
self.dialect = dialect
self.memo = {}
def visit_metadata(self, metadata):
if self.tables is not None:
tables = self.tables
else:
tables = list(metadata.tables.values())
try:
unsorted_tables = [t for t in tables if self._can_drop_table(t)]
collection = list(
reversed(
sort_tables_and_constraints(
unsorted_tables,
filter_fn=lambda constraint: False
if not self.dialect.supports_alter
or constraint.name is None
else None,
)
)
)
except exc.CircularDependencyError as err2:
if not self.dialect.supports_alter:
util.warn(
"Can't sort tables for DROP; an "
"unresolvable foreign key "
"dependency exists between tables: %s; and backend does "
"not support ALTER. To restore at least a partial sort, "
"apply use_alter=True to ForeignKey and "
"ForeignKeyConstraint "
"objects involved in the cycle to mark these as known "
"cycles that will be ignored."
% (", ".join(sorted([t.fullname for t in err2.cycles])))
)
collection = [(t, ()) for t in unsorted_tables]
else:
util.raise_(
exc.CircularDependencyError(
err2.args[0],
err2.cycles,
err2.edges,
msg="Can't sort tables for DROP; an "
"unresolvable foreign key "
"dependency exists between tables: %s. Please ensure "
"that the ForeignKey and ForeignKeyConstraint objects "
"involved in the cycle have "
"names so that they can be dropped using "
"DROP CONSTRAINT."
% (
", ".join(
sorted([t.fullname for t in err2.cycles])
)
),
),
from_=err2,
)
seq_coll = [
s
for s in metadata._sequences.values()
if self._can_drop_sequence(s)
]
event_collection = [t for (t, fks) in collection if t is not None]
metadata.dispatch.before_drop(
metadata,
self.connection,
tables=event_collection,
checkfirst=self.checkfirst,
_ddl_runner=self,
)
for table, fkcs in collection:
if table is not None:
self.traverse_single(
table,
drop_ok=True,
_is_metadata_operation=True,
_ignore_sequences=seq_coll,
)
else:
for fkc in fkcs:
self.traverse_single(fkc)
for seq in seq_coll:
self.traverse_single(seq, drop_ok=seq.column is None)
metadata.dispatch.after_drop(
metadata,
self.connection,
tables=event_collection,
checkfirst=self.checkfirst,
_ddl_runner=self,
)
def _can_drop_table(self, table):
self.dialect.validate_identifier(table.name)
effective_schema = self.connection.schema_for_object(table)
if effective_schema:
self.dialect.validate_identifier(effective_schema)
return not self.checkfirst or self.dialect.has_table(
self.connection, table.name, schema=effective_schema
)
def _can_drop_sequence(self, sequence):
effective_schema = self.connection.schema_for_object(sequence)
return self.dialect.supports_sequences and (
(not self.dialect.sequences_optional or not sequence.optional)
and (
not self.checkfirst
or self.dialect.has_sequence(
self.connection, sequence.name, schema=effective_schema
)
)
)
def visit_index(self, index):
self.connection.execute(DropIndex(index))
def visit_table(
self,
table,
drop_ok=False,
_is_metadata_operation=False,
_ignore_sequences=[],
):
if not drop_ok and not self._can_drop_table(table):
return
table.dispatch.before_drop(
table,
self.connection,
checkfirst=self.checkfirst,
_ddl_runner=self,
_is_metadata_operation=_is_metadata_operation,
)
self.connection.execute(DropTable(table))
# traverse client side defaults which may refer to server-side
# sequences. noting that some of these client side defaults may also be
# set up as server side defaults (see http://docs.sqlalchemy.org/en/
# latest/core/defaults.html#associating-a-sequence-as-the-server-side-
# default), so have to be dropped after the table is dropped.
for column in table.columns:
if (
column.default is not None
and column.default not in _ignore_sequences
):
self.traverse_single(column.default)
table.dispatch.after_drop(
table,
self.connection,
checkfirst=self.checkfirst,
_ddl_runner=self,
_is_metadata_operation=_is_metadata_operation,
)
def visit_foreign_key_constraint(self, constraint):
if not self.dialect.supports_alter:
return
self.connection.execute(DropConstraint(constraint))
def visit_sequence(self, sequence, drop_ok=False):
if not drop_ok and not self._can_drop_sequence(sequence):
return
self.connection.execute(DropSequence(sequence))
def sort_tables(
tables,
skip_fn=None,
extra_dependencies=None,
):
"""Sort a collection of :class:`_schema.Table` objects based on
dependency.
This is a dependency-ordered sort which will emit :class:`_schema.Table`
objects such that they will follow their dependent :class:`_schema.Table`
objects.
Tables are dependent on another based on the presence of
:class:`_schema.ForeignKeyConstraint`
objects as well as explicit dependencies
added by :meth:`_schema.Table.add_is_dependent_on`.
.. warning::
The :func:`._schema.sort_tables` function cannot by itself
accommodate automatic resolution of dependency cycles between
tables, which are usually caused by mutually dependent foreign key
constraints. When these cycles are detected, the foreign keys
of these tables are omitted from consideration in the sort.
A warning is emitted when this condition occurs, which will be an
exception raise in a future release. Tables which are not part
of the cycle will still be returned in dependency order.
To resolve these cycles, the
:paramref:`_schema.ForeignKeyConstraint.use_alter` parameter may be
applied to those constraints which create a cycle. Alternatively,
the :func:`_schema.sort_tables_and_constraints` function will
automatically return foreign key constraints in a separate
collection when cycles are detected so that they may be applied
to a schema separately.
.. versionchanged:: 1.3.17 - a warning is emitted when
:func:`_schema.sort_tables` cannot perform a proper sort due to
cyclical dependencies. This will be an exception in a future
release. Additionally, the sort will continue to return
other tables not involved in the cycle in dependency order
which was not the case previously.
:param tables: a sequence of :class:`_schema.Table` objects.
:param skip_fn: optional callable which will be passed a
:class:`_schema.ForeignKey` object; if it returns True, this
constraint will not be considered as a dependency. Note this is
**different** from the same parameter in
:func:`.sort_tables_and_constraints`, which is
instead passed the owning :class:`_schema.ForeignKeyConstraint` object.
:param extra_dependencies: a sequence of 2-tuples of tables which will
also be considered as dependent on each other.
.. seealso::
:func:`.sort_tables_and_constraints`
:attr:`_schema.MetaData.sorted_tables` - uses this function to sort
"""
if skip_fn is not None:
def _skip_fn(fkc):
for fk in fkc.elements:
if skip_fn(fk):
return True
else:
return None
else:
_skip_fn = None
return [
t
for (t, fkcs) in sort_tables_and_constraints(
tables,
filter_fn=_skip_fn,
extra_dependencies=extra_dependencies,
_warn_for_cycles=True,
)
if t is not None
]
def sort_tables_and_constraints(
tables, filter_fn=None, extra_dependencies=None, _warn_for_cycles=False
):
"""Sort a collection of :class:`_schema.Table` /
:class:`_schema.ForeignKeyConstraint`
objects.
This is a dependency-ordered sort which will emit tuples of
``(Table, [ForeignKeyConstraint, ...])`` such that each
:class:`_schema.Table` follows its dependent :class:`_schema.Table`
objects.
Remaining :class:`_schema.ForeignKeyConstraint`
objects that are separate due to
dependency rules not satisfied by the sort are emitted afterwards
as ``(None, [ForeignKeyConstraint ...])``.
Tables are dependent on another based on the presence of
:class:`_schema.ForeignKeyConstraint` objects, explicit dependencies
added by :meth:`_schema.Table.add_is_dependent_on`,
as well as dependencies
stated here using the :paramref:`~.sort_tables_and_constraints.skip_fn`
and/or :paramref:`~.sort_tables_and_constraints.extra_dependencies`
parameters.
:param tables: a sequence of :class:`_schema.Table` objects.
:param filter_fn: optional callable which will be passed a
:class:`_schema.ForeignKeyConstraint` object,
and returns a value based on
whether this constraint should definitely be included or excluded as
an inline constraint, or neither. If it returns False, the constraint
will definitely be included as a dependency that cannot be subject
to ALTER; if True, it will **only** be included as an ALTER result at
the end. Returning None means the constraint is included in the
table-based result unless it is detected as part of a dependency cycle.
:param extra_dependencies: a sequence of 2-tuples of tables which will
also be considered as dependent on each other.
.. versionadded:: 1.0.0
.. seealso::
:func:`.sort_tables`
"""
fixed_dependencies = set()
mutable_dependencies = set()
if extra_dependencies is not None:
fixed_dependencies.update(extra_dependencies)
remaining_fkcs = set()
for table in tables:
for fkc in table.foreign_key_constraints:
if fkc.use_alter is True:
remaining_fkcs.add(fkc)
continue
if filter_fn:
filtered = filter_fn(fkc)
if filtered is True:
remaining_fkcs.add(fkc)
continue
dependent_on = fkc.referred_table
if dependent_on is not table:
mutable_dependencies.add((dependent_on, table))
fixed_dependencies.update(
(parent, table) for parent in table._extra_dependencies
)
try:
candidate_sort = list(
topological.sort(
fixed_dependencies.union(mutable_dependencies),
tables,
deterministic_order=True,
)
)
except exc.CircularDependencyError as err:
if _warn_for_cycles:
util.warn(
"Cannot correctly sort tables; there are unresolvable cycles "
'between tables "%s", which is usually caused by mutually '
"dependent foreign key constraints. Foreign key constraints "
"involving these tables will not be considered; this warning "
"may raise an error in a future release."
% (", ".join(sorted(t.fullname for t in err.cycles)),)
)
for edge in err.edges:
if edge in mutable_dependencies:
table = edge[1]
if table not in err.cycles:
continue
can_remove = [
fkc
for fkc in table.foreign_key_constraints
if filter_fn is None or filter_fn(fkc) is not False
]
remaining_fkcs.update(can_remove)
for fkc in can_remove:
dependent_on = fkc.referred_table
if dependent_on is not table:
mutable_dependencies.discard((dependent_on, table))
candidate_sort = list(
topological.sort(
fixed_dependencies.union(mutable_dependencies),
tables,
deterministic_order=True,
)
)
return [
(table, table.foreign_key_constraints.difference(remaining_fkcs))
for table in candidate_sort
] + [(None, list(remaining_fkcs))]
PK ! B compiler.pynu [ # sql/compiler.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Base SQL and DDL compiler implementations.
Classes provided include:
:class:`.compiler.SQLCompiler` - renders SQL
strings
:class:`.compiler.DDLCompiler` - renders DDL
(data definition language) strings
:class:`.compiler.GenericTypeCompiler` - renders
type specification strings.
To generate user-defined SQL strings, see
:doc:`/ext/compiler`.
"""
import contextlib
import itertools
import re
from . import crud
from . import elements
from . import functions
from . import operators
from . import schema
from . import selectable
from . import sqltypes
from . import visitors
from .. import exc
from .. import util
RESERVED_WORDS = set(
[
"all",
"analyse",
"analyze",
"and",
"any",
"array",
"as",
"asc",
"asymmetric",
"authorization",
"between",
"binary",
"both",
"case",
"cast",
"check",
"collate",
"column",
"constraint",
"create",
"cross",
"current_date",
"current_role",
"current_time",
"current_timestamp",
"current_user",
"default",
"deferrable",
"desc",
"distinct",
"do",
"else",
"end",
"except",
"false",
"for",
"foreign",
"freeze",
"from",
"full",
"grant",
"group",
"having",
"ilike",
"in",
"initially",
"inner",
"intersect",
"into",
"is",
"isnull",
"join",
"leading",
"left",
"like",
"limit",
"localtime",
"localtimestamp",
"natural",
"new",
"not",
"notnull",
"null",
"off",
"offset",
"old",
"on",
"only",
"or",
"order",
"outer",
"overlaps",
"placing",
"primary",
"references",
"right",
"select",
"session_user",
"set",
"similar",
"some",
"symmetric",
"table",
"then",
"to",
"trailing",
"true",
"union",
"unique",
"user",
"using",
"verbose",
"when",
"where",
]
)
LEGAL_CHARACTERS = re.compile(r"^[A-Z0-9_$]+$", re.I)
LEGAL_CHARACTERS_PLUS_SPACE = re.compile(r"^[A-Z0-9_ $]+$", re.I)
ILLEGAL_INITIAL_CHARACTERS = {str(x) for x in range(0, 10)}.union(["$"])
FK_ON_DELETE = re.compile(
r"^(?:RESTRICT|CASCADE|SET NULL|NO ACTION|SET DEFAULT)$", re.I
)
FK_ON_UPDATE = re.compile(
r"^(?:RESTRICT|CASCADE|SET NULL|NO ACTION|SET DEFAULT)$", re.I
)
FK_INITIALLY = re.compile(r"^(?:DEFERRED|IMMEDIATE)$", re.I)
BIND_PARAMS = re.compile(r"(? ",
operators.ge: " >= ",
operators.eq: " = ",
operators.is_distinct_from: " IS DISTINCT FROM ",
operators.isnot_distinct_from: " IS NOT DISTINCT FROM ",
operators.concat_op: " || ",
operators.match_op: " MATCH ",
operators.notmatch_op: " NOT MATCH ",
operators.in_op: " IN ",
operators.notin_op: " NOT IN ",
operators.comma_op: ", ",
operators.from_: " FROM ",
operators.as_: " AS ",
operators.is_: " IS ",
operators.isnot: " IS NOT ",
operators.collate: " COLLATE ",
# unary
operators.exists: "EXISTS ",
operators.distinct_op: "DISTINCT ",
operators.inv: "NOT ",
operators.any_op: "ANY ",
operators.all_op: "ALL ",
# modifiers
operators.desc_op: " DESC",
operators.asc_op: " ASC",
operators.nullsfirst_op: " NULLS FIRST",
operators.nullslast_op: " NULLS LAST",
}
FUNCTIONS = {
functions.coalesce: "coalesce",
functions.current_date: "CURRENT_DATE",
functions.current_time: "CURRENT_TIME",
functions.current_timestamp: "CURRENT_TIMESTAMP",
functions.current_user: "CURRENT_USER",
functions.localtime: "LOCALTIME",
functions.localtimestamp: "LOCALTIMESTAMP",
functions.random: "random",
functions.sysdate: "sysdate",
functions.session_user: "SESSION_USER",
functions.user: "USER",
functions.cube: "CUBE",
functions.rollup: "ROLLUP",
functions.grouping_sets: "GROUPING SETS",
}
EXTRACT_MAP = {
"month": "month",
"day": "day",
"year": "year",
"second": "second",
"hour": "hour",
"doy": "doy",
"minute": "minute",
"quarter": "quarter",
"dow": "dow",
"week": "week",
"epoch": "epoch",
"milliseconds": "milliseconds",
"microseconds": "microseconds",
"timezone_hour": "timezone_hour",
"timezone_minute": "timezone_minute",
}
COMPOUND_KEYWORDS = {
selectable.CompoundSelect.UNION: "UNION",
selectable.CompoundSelect.UNION_ALL: "UNION ALL",
selectable.CompoundSelect.EXCEPT: "EXCEPT",
selectable.CompoundSelect.EXCEPT_ALL: "EXCEPT ALL",
selectable.CompoundSelect.INTERSECT: "INTERSECT",
selectable.CompoundSelect.INTERSECT_ALL: "INTERSECT ALL",
}
class Compiled(object):
"""Represent a compiled SQL or DDL expression.
The ``__str__`` method of the ``Compiled`` object should produce
the actual text of the statement. ``Compiled`` objects are
specific to their underlying database dialect, and also may
or may not be specific to the columns referenced within a
particular set of bind parameters. In no case should the
``Compiled`` object be dependent on the actual values of those
bind parameters, even though it may reference those values as
defaults.
"""
_cached_metadata = None
schema_translate_map = None
execution_options = util.immutabledict()
"""
Execution options propagated from the statement. In some cases,
sub-elements of the statement can modify these.
"""
def __init__(
self,
dialect,
statement,
bind=None,
schema_translate_map=None,
compile_kwargs=util.immutabledict(),
):
"""Construct a new :class:`.Compiled` object.
:param dialect: :class:`.Dialect` to compile against.
:param statement: :class:`_expression.ClauseElement` to be compiled.
:param bind: Optional Engine or Connection to compile this
statement against.
:param schema_translate_map: dictionary of schema names to be
translated when forming the resultant SQL
.. versionadded:: 1.1
.. seealso::
:ref:`schema_translating`
:param compile_kwargs: additional kwargs that will be
passed to the initial call to :meth:`.Compiled.process`.
"""
self.dialect = dialect
self.bind = bind
self.preparer = self.dialect.identifier_preparer
self.schema_translate_map = schema_translate_map
if schema_translate_map:
self.preparer = self.preparer._with_schema_translate(
schema_translate_map
)
if statement is not None:
self.statement = statement
self.can_execute = statement.supports_execution
if self.can_execute:
self.execution_options = statement._execution_options
self.string = self.process(self.statement, **compile_kwargs)
@util.deprecated(
"0.7",
"The :meth:`.Compiled.compile` method is deprecated and will be "
"removed in a future release. The :class:`.Compiled` object "
"now runs its compilation within the constructor, and this method "
"does nothing.",
)
def compile(self):
"""Produce the internal string representation of this element."""
pass
def _execute_on_connection(self, connection, multiparams, params):
if self.can_execute:
return connection._execute_compiled(self, multiparams, params)
else:
raise exc.ObjectNotExecutableError(self.statement)
@property
def sql_compiler(self):
"""Return a Compiled that is capable of processing SQL expressions.
If this compiler is one, it would likely just return 'self'.
"""
raise NotImplementedError()
def process(self, obj, **kwargs):
return obj._compiler_dispatch(self, **kwargs)
def __str__(self):
"""Return the string text of the generated SQL or DDL."""
return self.string or ""
def construct_params(self, params=None):
"""Return the bind params for this compiled object.
:param params: a dict of string/object pairs whose values will
override bind values compiled in to the
statement.
"""
raise NotImplementedError()
@property
def params(self):
"""Return the bind params for this compiled object."""
return self.construct_params()
def execute(self, *multiparams, **params):
"""Execute this compiled object."""
e = self.bind
if e is None:
raise exc.UnboundExecutionError(
"This Compiled object is not bound to any Engine "
"or Connection.",
code="2afi",
)
return e._execute_compiled(self, multiparams, params)
def scalar(self, *multiparams, **params):
"""Execute this compiled object and return the result's
scalar value."""
return self.execute(*multiparams, **params).scalar()
class TypeCompiler(util.with_metaclass(util.EnsureKWArgType, object)):
"""Produces DDL specification for TypeEngine objects."""
ensure_kwarg = r"visit_\w+"
def __init__(self, dialect):
self.dialect = dialect
def process(self, type_, **kw):
return type_._compiler_dispatch(self, **kw)
class _CompileLabel(visitors.Visitable):
"""lightweight label object which acts as an expression.Label."""
__visit_name__ = "label"
__slots__ = "element", "name"
def __init__(self, col, name, alt_names=()):
self.element = col
self.name = name
self._alt_names = (col,) + alt_names
@property
def proxy_set(self):
return self.element.proxy_set
@property
def type(self):
return self.element.type
def self_group(self, **kw):
return self
class prefix_anon_map(dict):
"""A map that creates new keys for missing key access.
Considers keys of the form " " to produce
new symbols "_", where "index" is an incrementing integer
corresponding to .
Inlines the approach taken by :class:`sqlalchemy.util.PopulateDict` which
is otherwise usually used for this type of operation.
"""
def __missing__(self, key):
(ident, derived) = key.split(" ", 1)
anonymous_counter = self.get(derived, 1)
self[derived] = anonymous_counter + 1
value = derived + "_" + str(anonymous_counter)
self[key] = value
return value
class SQLCompiler(Compiled):
"""Default implementation of :class:`.Compiled`.
Compiles :class:`_expression.ClauseElement` objects into SQL strings.
"""
extract_map = EXTRACT_MAP
compound_keywords = COMPOUND_KEYWORDS
isdelete = isinsert = isupdate = False
"""class-level defaults which can be set at the instance
level to define if this Compiled instance represents
INSERT/UPDATE/DELETE
"""
isplaintext = False
returning = None
"""holds the "returning" collection of columns if
the statement is CRUD and defines returning columns
either implicitly or explicitly
"""
returning_precedes_values = False
"""set to True classwide to generate RETURNING
clauses before the VALUES or WHERE clause (i.e. MSSQL)
"""
render_table_with_column_in_update_from = False
"""set to True classwide to indicate the SET clause
in a multi-table UPDATE statement should qualify
columns with the table name (i.e. MySQL only)
"""
contains_expanding_parameters = False
"""True if we've encountered bindparam(..., expanding=True).
These need to be converted before execution time against the
string statement.
"""
ansi_bind_rules = False
"""SQL 92 doesn't allow bind parameters to be used
in the columns clause of a SELECT, nor does it allow
ambiguous expressions like "? = ?". A compiler
subclass can set this flag to False if the target
driver/DB enforces this
"""
_textual_ordered_columns = False
"""tell the result object that the column names as rendered are important,
but they are also "ordered" vs. what is in the compiled object here.
"""
_ordered_columns = True
"""
if False, means we can't be sure the list of entries
in _result_columns is actually the rendered order. Usually
True unless using an unordered TextAsFrom.
"""
_numeric_binds = False
"""
True if paramstyle is "numeric". This paramstyle is trickier than
all the others.
"""
insert_single_values_expr = None
"""When an INSERT is compiled with a single set of parameters inside
a VALUES expression, the string is assigned here, where it can be
used for insert batching schemes to rewrite the VALUES expression.
.. versionadded:: 1.3.8
"""
insert_prefetch = update_prefetch = ()
def __init__(
self, dialect, statement, column_keys=None, inline=False, **kwargs
):
"""Construct a new :class:`.SQLCompiler` object.
:param dialect: :class:`.Dialect` to be used
:param statement: :class:`_expression.ClauseElement` to be compiled
:param column_keys: a list of column names to be compiled into an
INSERT or UPDATE statement.
:param inline: whether to generate INSERT statements as "inline", e.g.
not formatted to return any generated defaults
:param kwargs: additional keyword arguments to be consumed by the
superclass.
"""
self.column_keys = column_keys
# compile INSERT/UPDATE defaults/sequences inlined (no pre-
# execute)
self.inline = inline or getattr(statement, "inline", False)
# a dictionary of bind parameter keys to BindParameter
# instances.
self.binds = {}
# a dictionary of BindParameter instances to "compiled" names
# that are actually present in the generated SQL
self.bind_names = util.column_dict()
# stack which keeps track of nested SELECT statements
self.stack = []
# relates label names in the final SQL to a tuple of local
# column/label name, ColumnElement object (if any) and
# TypeEngine. ResultProxy uses this for type processing and
# column targeting
self._result_columns = []
# true if the paramstyle is positional
self.positional = dialect.positional
if self.positional:
self.positiontup = []
self._numeric_binds = dialect.paramstyle == "numeric"
self.bindtemplate = BIND_TEMPLATES[dialect.paramstyle]
self.ctes = None
self.label_length = (
dialect.label_length or dialect.max_identifier_length
)
# a map which tracks "anonymous" identifiers that are created on
# the fly here
self.anon_map = prefix_anon_map()
# a map which tracks "truncated" names based on
# dialect.label_length or dialect.max_identifier_length
self.truncated_names = {}
Compiled.__init__(self, dialect, statement, **kwargs)
if (
self.isinsert or self.isupdate or self.isdelete
) and statement._returning:
self.returning = statement._returning
if self.positional and self._numeric_binds:
self._apply_numbered_params()
@property
def current_executable(self):
"""Return the current 'executable' that is being compiled.
This is currently the :class:`_sql.Select`, :class:`_sql.Insert`,
:class:`_sql.Update`, :class:`_sql.Delete`,
:class:`_sql.CompoundSelect` object that is being compiled.
Specifically it's assigned to the ``self.stack`` list of elements.
When a statement like the above is being compiled, it normally
is also assigned to the ``.statement`` attribute of the
:class:`_sql.Compiler` object. However, all SQL constructs are
ultimately nestable, and this attribute should never be consulted
by a ``visit_`` method, as it is not guaranteed to be assigned
nor guaranteed to correspond to the current statement being compiled.
.. versionadded:: 1.3.21
For compatibility with previous versions, use the following
recipe::
statement = getattr(self, "current_executable", False)
if statement is False:
statement = self.stack[-1]["selectable"]
For versions 1.4 and above, ensure only .current_executable
is used; the format of "self.stack" may change.
"""
try:
return self.stack[-1]["selectable"]
except IndexError as ie:
util.raise_(
IndexError("Compiler does not have a stack entry"),
replace_context=ie,
)
@property
def prefetch(self):
return list(self.insert_prefetch + self.update_prefetch)
@util.memoized_instancemethod
def _init_cte_state(self):
"""Initialize collections related to CTEs only if
a CTE is located, to save on the overhead of
these collections otherwise.
"""
# collect CTEs to tack on top of a SELECT
self.ctes = util.OrderedDict()
self.ctes_by_name = {}
self.ctes_recursive = False
if self.positional:
self.cte_positional = {}
@contextlib.contextmanager
def _nested_result(self):
"""special API to support the use case of 'nested result sets'"""
result_columns, ordered_columns = (
self._result_columns,
self._ordered_columns,
)
self._result_columns, self._ordered_columns = [], False
try:
if self.stack:
entry = self.stack[-1]
entry["need_result_map_for_nested"] = True
else:
entry = None
yield self._result_columns, self._ordered_columns
finally:
if entry:
entry.pop("need_result_map_for_nested")
self._result_columns, self._ordered_columns = (
result_columns,
ordered_columns,
)
def _apply_numbered_params(self):
poscount = itertools.count(1)
self.string = re.sub(
r"\[_POSITION\]", lambda m: str(util.next(poscount)), self.string
)
@util.memoized_property
def _bind_processors(self):
return dict(
(key, value)
for key, value in (
(
self.bind_names[bindparam],
bindparam.type._cached_bind_processor(self.dialect),
)
for bindparam in self.bind_names
)
if value is not None
)
def is_subquery(self):
return len(self.stack) > 1
@property
def sql_compiler(self):
return self
def construct_params(self, params=None, _group_number=None, _check=True):
"""return a dictionary of bind parameter keys and values"""
if params:
pd = {}
for bindparam in self.bind_names:
name = self.bind_names[bindparam]
if bindparam.key in params:
pd[name] = params[bindparam.key]
elif name in params:
pd[name] = params[name]
elif _check and bindparam.required:
if _group_number:
raise exc.InvalidRequestError(
"A value is required for bind parameter %r, "
"in parameter group %d"
% (bindparam.key, _group_number),
code="cd3x",
)
else:
raise exc.InvalidRequestError(
"A value is required for bind parameter %r"
% bindparam.key,
code="cd3x",
)
elif bindparam.callable:
pd[name] = bindparam.effective_value
else:
pd[name] = bindparam.value
return pd
else:
pd = {}
for bindparam in self.bind_names:
if _check and bindparam.required:
if _group_number:
raise exc.InvalidRequestError(
"A value is required for bind parameter %r, "
"in parameter group %d"
% (bindparam.key, _group_number),
code="cd3x",
)
else:
raise exc.InvalidRequestError(
"A value is required for bind parameter %r"
% bindparam.key,
code="cd3x",
)
if bindparam.callable:
pd[self.bind_names[bindparam]] = bindparam.effective_value
else:
pd[self.bind_names[bindparam]] = bindparam.value
return pd
@property
def params(self):
"""Return the bind param dictionary embedded into this
compiled object, for those values that are present."""
return self.construct_params(_check=False)
@util.dependencies("sqlalchemy.engine.result")
def _create_result_map(self, result):
"""utility method used for unit tests only."""
return result.ResultMetaData._create_result_map(self._result_columns)
def default_from(self):
"""Called when a SELECT statement has no froms, and no FROM clause is
to be appended.
Gives Oracle a chance to tack on a ``FROM DUAL`` to the string output.
"""
return ""
def visit_grouping(self, grouping, asfrom=False, **kwargs):
return "(" + grouping.element._compiler_dispatch(self, **kwargs) + ")"
def visit_label_reference(
self, element, within_columns_clause=False, **kwargs
):
if self.stack and self.dialect.supports_simple_order_by_label:
selectable = self.stack[-1]["selectable"]
with_cols, only_froms, only_cols = selectable._label_resolve_dict
if within_columns_clause:
resolve_dict = only_froms
else:
resolve_dict = only_cols
# this can be None in the case that a _label_reference()
# were subject to a replacement operation, in which case
# the replacement of the Label element may have changed
# to something else like a ColumnClause expression.
order_by_elem = element.element._order_by_label_element
if (
order_by_elem is not None
and order_by_elem.name in resolve_dict
and order_by_elem.shares_lineage(
resolve_dict[order_by_elem.name]
)
):
kwargs[
"render_label_as_label"
] = element.element._order_by_label_element
return self.process(
element.element,
within_columns_clause=within_columns_clause,
**kwargs
)
def visit_textual_label_reference(
self, element, within_columns_clause=False, **kwargs
):
if not self.stack:
# compiling the element outside of the context of a SELECT
return self.process(element._text_clause)
selectable = self.stack[-1]["selectable"]
with_cols, only_froms, only_cols = selectable._label_resolve_dict
try:
if within_columns_clause:
col = only_froms[element.element]
else:
col = with_cols[element.element]
except KeyError as ke:
elements._no_text_coercion(
element.element,
exc.CompileError,
"Can't resolve label reference for ORDER BY / "
"GROUP BY / DISTINCT etc.",
err=ke,
)
else:
kwargs["render_label_as_label"] = col
return self.process(
col, within_columns_clause=within_columns_clause, **kwargs
)
def visit_label(
self,
label,
add_to_result_map=None,
within_label_clause=False,
within_columns_clause=False,
render_label_as_label=None,
**kw
):
# only render labels within the columns clause
# or ORDER BY clause of a select. dialect-specific compilers
# can modify this behavior.
render_label_with_as = (
within_columns_clause and not within_label_clause
)
render_label_only = render_label_as_label is label
if render_label_only or render_label_with_as:
if isinstance(label.name, elements._truncated_label):
labelname = self._truncated_identifier("colident", label.name)
else:
labelname = label.name
if render_label_with_as:
if add_to_result_map is not None:
add_to_result_map(
labelname,
label.name,
(label, labelname) + label._alt_names,
label.type,
)
return (
label.element._compiler_dispatch(
self,
within_columns_clause=True,
within_label_clause=True,
**kw
)
+ OPERATORS[operators.as_]
+ self.preparer.format_label(label, labelname)
)
elif render_label_only:
return self.preparer.format_label(label, labelname)
else:
return label.element._compiler_dispatch(
self, within_columns_clause=False, **kw
)
def _fallback_column_name(self, column):
raise exc.CompileError(
"Cannot compile Column object until " "its 'name' is assigned."
)
def visit_column(
self, column, add_to_result_map=None, include_table=True, **kwargs
):
name = orig_name = column.name
if name is None:
name = self._fallback_column_name(column)
is_literal = column.is_literal
if not is_literal and isinstance(name, elements._truncated_label):
name = self._truncated_identifier("colident", name)
if add_to_result_map is not None:
add_to_result_map(
name, orig_name, (column, name, column.key), column.type
)
if is_literal:
# note we are not currently accommodating for
# literal_column(quoted_name('ident', True)) here
name = self.escape_literal_column(name)
else:
name = self.preparer.quote(name)
table = column.table
if table is None or not include_table or not table.named_with_column:
return name
else:
effective_schema = self.preparer.schema_for_object(table)
if effective_schema:
schema_prefix = (
self.preparer.quote_schema(effective_schema) + "."
)
else:
schema_prefix = ""
tablename = table.name
if isinstance(tablename, elements._truncated_label):
tablename = self._truncated_identifier("alias", tablename)
return schema_prefix + self.preparer.quote(tablename) + "." + name
def visit_collation(self, element, **kw):
return self.preparer.format_collation(element.collation)
def visit_fromclause(self, fromclause, **kwargs):
return fromclause.name
def visit_index(self, index, **kwargs):
return index.name
def visit_typeclause(self, typeclause, **kw):
kw["type_expression"] = typeclause
return self.dialect.type_compiler.process(typeclause.type, **kw)
def post_process_text(self, text):
if self.preparer._double_percents:
text = text.replace("%", "%%")
return text
def escape_literal_column(self, text):
if self.preparer._double_percents:
text = text.replace("%", "%%")
return text
def visit_textclause(self, textclause, **kw):
def do_bindparam(m):
name = m.group(1)
if name in textclause._bindparams:
return self.process(textclause._bindparams[name], **kw)
else:
return self.bindparam_string(name, **kw)
if not self.stack:
self.isplaintext = True
# un-escape any \:params
return BIND_PARAMS_ESC.sub(
lambda m: m.group(1),
BIND_PARAMS.sub(
do_bindparam, self.post_process_text(textclause.text)
),
)
def visit_text_as_from(
self, taf, compound_index=None, asfrom=False, parens=True, **kw
):
toplevel = not self.stack
entry = self._default_stack_entry if toplevel else self.stack[-1]
populate_result_map = (
toplevel
or (
compound_index == 0
and entry.get("need_result_map_for_compound", False)
)
or entry.get("need_result_map_for_nested", False)
)
if populate_result_map:
self._ordered_columns = (
self._textual_ordered_columns
) = taf.positional
for c in taf.column_args:
self.process(
c,
within_columns_clause=True,
add_to_result_map=self._add_to_result_map,
)
text = self.process(taf.element, **kw)
if asfrom and parens:
text = "(%s)" % text
return text
def visit_null(self, expr, **kw):
return "NULL"
def visit_true(self, expr, **kw):
if self.dialect.supports_native_boolean:
return "true"
else:
return "1"
def visit_false(self, expr, **kw):
if self.dialect.supports_native_boolean:
return "false"
else:
return "0"
def visit_clauselist(self, clauselist, **kw):
sep = clauselist.operator
if sep is None:
sep = " "
else:
sep = OPERATORS[clauselist.operator]
text = sep.join(
s
for s in (
c._compiler_dispatch(self, **kw) for c in clauselist.clauses
)
if s
)
if clauselist._tuple_values and self.dialect.tuple_in_values:
text = "VALUES " + text
return text
def visit_case(self, clause, **kwargs):
x = "CASE "
if clause.value is not None:
x += clause.value._compiler_dispatch(self, **kwargs) + " "
for cond, result in clause.whens:
x += (
"WHEN "
+ cond._compiler_dispatch(self, **kwargs)
+ " THEN "
+ result._compiler_dispatch(self, **kwargs)
+ " "
)
if clause.else_ is not None:
x += (
"ELSE " + clause.else_._compiler_dispatch(self, **kwargs) + " "
)
x += "END"
return x
def visit_type_coerce(self, type_coerce, **kw):
return type_coerce.typed_expression._compiler_dispatch(self, **kw)
def visit_cast(self, cast, **kwargs):
return "CAST(%s AS %s)" % (
cast.clause._compiler_dispatch(self, **kwargs),
cast.typeclause._compiler_dispatch(self, **kwargs),
)
def _format_frame_clause(self, range_, **kw):
return "%s AND %s" % (
"UNBOUNDED PRECEDING"
if range_[0] is elements.RANGE_UNBOUNDED
else "CURRENT ROW"
if range_[0] is elements.RANGE_CURRENT
else "%s PRECEDING"
% (self.process(elements.literal(abs(range_[0])), **kw),)
if range_[0] < 0
else "%s FOLLOWING"
% (self.process(elements.literal(range_[0]), **kw),),
"UNBOUNDED FOLLOWING"
if range_[1] is elements.RANGE_UNBOUNDED
else "CURRENT ROW"
if range_[1] is elements.RANGE_CURRENT
else "%s PRECEDING"
% (self.process(elements.literal(abs(range_[1])), **kw),)
if range_[1] < 0
else "%s FOLLOWING"
% (self.process(elements.literal(range_[1]), **kw),),
)
def visit_over(self, over, **kwargs):
if over.range_:
range_ = "RANGE BETWEEN %s" % self._format_frame_clause(
over.range_, **kwargs
)
elif over.rows:
range_ = "ROWS BETWEEN %s" % self._format_frame_clause(
over.rows, **kwargs
)
else:
range_ = None
return "%s OVER (%s)" % (
over.element._compiler_dispatch(self, **kwargs),
" ".join(
[
"%s BY %s"
% (word, clause._compiler_dispatch(self, **kwargs))
for word, clause in (
("PARTITION", over.partition_by),
("ORDER", over.order_by),
)
if clause is not None and len(clause)
]
+ ([range_] if range_ else [])
),
)
def visit_withingroup(self, withingroup, **kwargs):
return "%s WITHIN GROUP (ORDER BY %s)" % (
withingroup.element._compiler_dispatch(self, **kwargs),
withingroup.order_by._compiler_dispatch(self, **kwargs),
)
def visit_funcfilter(self, funcfilter, **kwargs):
return "%s FILTER (WHERE %s)" % (
funcfilter.func._compiler_dispatch(self, **kwargs),
funcfilter.criterion._compiler_dispatch(self, **kwargs),
)
def visit_extract(self, extract, **kwargs):
field = self.extract_map.get(extract.field, extract.field)
return "EXTRACT(%s FROM %s)" % (
field,
extract.expr._compiler_dispatch(self, **kwargs),
)
def visit_function(self, func, add_to_result_map=None, **kwargs):
if add_to_result_map is not None:
add_to_result_map(func.name, func.name, (), func.type)
disp = getattr(self, "visit_%s_func" % func.name.lower(), None)
if disp:
return disp(func, **kwargs)
else:
name = FUNCTIONS.get(func.__class__, None)
if name:
if func._has_args:
name += "%(expr)s"
else:
name = func.name
name = (
self.preparer.quote(name)
if self.preparer._requires_quotes_illegal_chars(name)
or isinstance(name, elements.quoted_name)
else name
)
name = name + "%(expr)s"
return ".".join(
[
(
self.preparer.quote(tok)
if self.preparer._requires_quotes_illegal_chars(tok)
or isinstance(name, elements.quoted_name)
else tok
)
for tok in func.packagenames
]
+ [name]
) % {"expr": self.function_argspec(func, **kwargs)}
def visit_next_value_func(self, next_value, **kw):
return self.visit_sequence(next_value.sequence)
def visit_sequence(self, sequence, **kw):
raise NotImplementedError(
"Dialect '%s' does not support sequence increments."
% self.dialect.name
)
def function_argspec(self, func, **kwargs):
return func.clause_expr._compiler_dispatch(self, **kwargs)
def visit_compound_select(
self, cs, asfrom=False, parens=True, compound_index=0, **kwargs
):
toplevel = not self.stack
entry = self._default_stack_entry if toplevel else self.stack[-1]
need_result_map = toplevel or (
compound_index == 0
and entry.get("need_result_map_for_compound", False)
)
self.stack.append(
{
"correlate_froms": entry["correlate_froms"],
"asfrom_froms": entry["asfrom_froms"],
"selectable": cs,
"need_result_map_for_compound": need_result_map,
}
)
keyword = self.compound_keywords.get(cs.keyword)
text = (" " + keyword + " ").join(
(
c._compiler_dispatch(
self,
asfrom=asfrom,
parens=False,
compound_index=i,
**kwargs
)
for i, c in enumerate(cs.selects)
)
)
text += self.group_by_clause(cs, **dict(asfrom=asfrom, **kwargs))
text += self.order_by_clause(cs, **kwargs)
text += (
(cs._limit_clause is not None or cs._offset_clause is not None)
and self.limit_clause(cs, **kwargs)
or ""
)
if self.ctes and toplevel:
text = self._render_cte_clause() + text
self.stack.pop(-1)
if asfrom and parens:
return "(" + text + ")"
else:
return text
def _get_operator_dispatch(self, operator_, qualifier1, qualifier2):
attrname = "visit_%s_%s%s" % (
operator_.__name__,
qualifier1,
"_" + qualifier2 if qualifier2 else "",
)
return getattr(self, attrname, None)
def visit_unary(self, unary, **kw):
if unary.operator:
if unary.modifier:
raise exc.CompileError(
"Unary expression does not support operator "
"and modifier simultaneously"
)
disp = self._get_operator_dispatch(
unary.operator, "unary", "operator"
)
if disp:
return disp(unary, unary.operator, **kw)
else:
return self._generate_generic_unary_operator(
unary, OPERATORS[unary.operator], **kw
)
elif unary.modifier:
disp = self._get_operator_dispatch(
unary.modifier, "unary", "modifier"
)
if disp:
return disp(unary, unary.modifier, **kw)
else:
return self._generate_generic_unary_modifier(
unary, OPERATORS[unary.modifier], **kw
)
else:
raise exc.CompileError(
"Unary expression has no operator or modifier"
)
def visit_istrue_unary_operator(self, element, operator, **kw):
if (
element._is_implicitly_boolean
or self.dialect.supports_native_boolean
):
return self.process(element.element, **kw)
else:
return "%s = 1" % self.process(element.element, **kw)
def visit_isfalse_unary_operator(self, element, operator, **kw):
if (
element._is_implicitly_boolean
or self.dialect.supports_native_boolean
):
return "NOT %s" % self.process(element.element, **kw)
else:
return "%s = 0" % self.process(element.element, **kw)
def visit_notmatch_op_binary(self, binary, operator, **kw):
return "NOT %s" % self.visit_binary(
binary, override_operator=operators.match_op
)
def _emit_empty_in_warning(self):
util.warn(
"The IN-predicate was invoked with an "
"empty sequence. This results in a "
"contradiction, which nonetheless can be "
"expensive to evaluate. Consider alternative "
"strategies for improved performance."
)
def visit_empty_in_op_binary(self, binary, operator, **kw):
if self.dialect._use_static_in:
return "1 != 1"
else:
if self.dialect._warn_on_empty_in:
self._emit_empty_in_warning()
return self.process(binary.left != binary.left)
def visit_empty_notin_op_binary(self, binary, operator, **kw):
if self.dialect._use_static_in:
return "1 = 1"
else:
if self.dialect._warn_on_empty_in:
self._emit_empty_in_warning()
return self.process(binary.left == binary.left)
def visit_empty_set_expr(self, element_types):
raise NotImplementedError(
"Dialect '%s' does not support empty set expression."
% self.dialect.name
)
def visit_binary(
self, binary, override_operator=None, eager_grouping=False, **kw
):
# don't allow "? = ?" to render
if (
self.ansi_bind_rules
and isinstance(binary.left, elements.BindParameter)
and isinstance(binary.right, elements.BindParameter)
):
kw["literal_binds"] = True
operator_ = override_operator or binary.operator
disp = self._get_operator_dispatch(operator_, "binary", None)
if disp:
return disp(binary, operator_, **kw)
else:
try:
opstring = OPERATORS[operator_]
except KeyError as err:
util.raise_(
exc.UnsupportedCompilationError(self, operator_),
replace_context=err,
)
else:
return self._generate_generic_binary(binary, opstring, **kw)
def visit_function_as_comparison_op_binary(self, element, operator, **kw):
return self.process(element.sql_function, **kw)
def visit_mod_binary(self, binary, operator, **kw):
if self.preparer._double_percents:
return (
self.process(binary.left, **kw)
+ " %% "
+ self.process(binary.right, **kw)
)
else:
return (
self.process(binary.left, **kw)
+ " % "
+ self.process(binary.right, **kw)
)
def visit_custom_op_binary(self, element, operator, **kw):
kw["eager_grouping"] = operator.eager_grouping
return self._generate_generic_binary(
element, " " + operator.opstring + " ", **kw
)
def visit_custom_op_unary_operator(self, element, operator, **kw):
return self._generate_generic_unary_operator(
element, operator.opstring + " ", **kw
)
def visit_custom_op_unary_modifier(self, element, operator, **kw):
return self._generate_generic_unary_modifier(
element, " " + operator.opstring, **kw
)
def _generate_generic_binary(
self, binary, opstring, eager_grouping=False, **kw
):
_in_binary = kw.get("_in_binary", False)
kw["_in_binary"] = True
text = (
binary.left._compiler_dispatch(
self, eager_grouping=eager_grouping, **kw
)
+ opstring
+ binary.right._compiler_dispatch(
self, eager_grouping=eager_grouping, **kw
)
)
if _in_binary and eager_grouping:
text = "(%s)" % text
return text
def _generate_generic_unary_operator(self, unary, opstring, **kw):
return opstring + unary.element._compiler_dispatch(self, **kw)
def _generate_generic_unary_modifier(self, unary, opstring, **kw):
return unary.element._compiler_dispatch(self, **kw) + opstring
@util.memoized_property
def _like_percent_literal(self):
return elements.literal_column("'%'", type_=sqltypes.STRINGTYPE)
def visit_contains_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__add__(binary.right).__add__(percent)
return self.visit_like_op_binary(binary, operator, **kw)
def visit_notcontains_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__add__(binary.right).__add__(percent)
return self.visit_notlike_op_binary(binary, operator, **kw)
def visit_startswith_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__radd__(binary.right)
return self.visit_like_op_binary(binary, operator, **kw)
def visit_notstartswith_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__radd__(binary.right)
return self.visit_notlike_op_binary(binary, operator, **kw)
def visit_endswith_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__add__(binary.right)
return self.visit_like_op_binary(binary, operator, **kw)
def visit_notendswith_op_binary(self, binary, operator, **kw):
binary = binary._clone()
percent = self._like_percent_literal
binary.right = percent.__add__(binary.right)
return self.visit_notlike_op_binary(binary, operator, **kw)
def visit_like_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
# TODO: use ternary here, not "and"/ "or"
return "%s LIKE %s" % (
binary.left._compiler_dispatch(self, **kw),
binary.right._compiler_dispatch(self, **kw),
) + (
" ESCAPE " + self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape
else ""
)
def visit_notlike_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
return "%s NOT LIKE %s" % (
binary.left._compiler_dispatch(self, **kw),
binary.right._compiler_dispatch(self, **kw),
) + (
" ESCAPE " + self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape
else ""
)
def visit_ilike_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
return "lower(%s) LIKE lower(%s)" % (
binary.left._compiler_dispatch(self, **kw),
binary.right._compiler_dispatch(self, **kw),
) + (
" ESCAPE " + self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape
else ""
)
def visit_notilike_op_binary(self, binary, operator, **kw):
escape = binary.modifiers.get("escape", None)
return "lower(%s) NOT LIKE lower(%s)" % (
binary.left._compiler_dispatch(self, **kw),
binary.right._compiler_dispatch(self, **kw),
) + (
" ESCAPE " + self.render_literal_value(escape, sqltypes.STRINGTYPE)
if escape
else ""
)
def visit_between_op_binary(self, binary, operator, **kw):
symmetric = binary.modifiers.get("symmetric", False)
return self._generate_generic_binary(
binary, " BETWEEN SYMMETRIC " if symmetric else " BETWEEN ", **kw
)
def visit_notbetween_op_binary(self, binary, operator, **kw):
symmetric = binary.modifiers.get("symmetric", False)
return self._generate_generic_binary(
binary,
" NOT BETWEEN SYMMETRIC " if symmetric else " NOT BETWEEN ",
**kw
)
def visit_bindparam(
self,
bindparam,
within_columns_clause=False,
literal_binds=False,
skip_bind_expression=False,
**kwargs
):
if not skip_bind_expression:
impl = bindparam.type.dialect_impl(self.dialect)
if impl._has_bind_expression:
bind_expression = impl.bind_expression(bindparam)
return self.process(
bind_expression,
skip_bind_expression=True,
within_columns_clause=within_columns_clause,
literal_binds=literal_binds,
**kwargs
)
if literal_binds or (within_columns_clause and self.ansi_bind_rules):
if bindparam.value is None and bindparam.callable is None:
raise exc.CompileError(
"Bind parameter '%s' without a "
"renderable value not allowed here." % bindparam.key
)
return self.render_literal_bindparam(
bindparam, within_columns_clause=True, **kwargs
)
name = self._truncate_bindparam(bindparam)
if name in self.binds:
existing = self.binds[name]
if existing is not bindparam:
if (
existing.unique or bindparam.unique
) and not existing.proxy_set.intersection(bindparam.proxy_set):
raise exc.CompileError(
"Bind parameter '%s' conflicts with "
"unique bind parameter of the same name"
% bindparam.key
)
elif existing._is_crud or bindparam._is_crud:
raise exc.CompileError(
"bindparam() name '%s' is reserved "
"for automatic usage in the VALUES or SET "
"clause of this "
"insert/update statement. Please use a "
"name other than column name when using bindparam() "
"with insert() or update() (for example, 'b_%s')."
% (bindparam.key, bindparam.key)
)
self.binds[bindparam.key] = self.binds[name] = bindparam
return self.bindparam_string(
name, expanding=bindparam.expanding, **kwargs
)
def render_literal_bindparam(self, bindparam, **kw):
value = bindparam.effective_value
return self.render_literal_value(value, bindparam.type)
def render_literal_value(self, value, type_):
"""Render the value of a bind parameter as a quoted literal.
This is used for statement sections that do not accept bind parameters
on the target driver/database.
This should be implemented by subclasses using the quoting services
of the DBAPI.
"""
processor = type_._cached_literal_processor(self.dialect)
if processor:
return processor(value)
else:
raise NotImplementedError(
"Don't know how to literal-quote value %r" % value
)
def _truncate_bindparam(self, bindparam):
if bindparam in self.bind_names:
return self.bind_names[bindparam]
bind_name = bindparam.key
if isinstance(bind_name, elements._truncated_label):
bind_name = self._truncated_identifier("bindparam", bind_name)
# add to bind_names for translation
self.bind_names[bindparam] = bind_name
return bind_name
def _truncated_identifier(self, ident_class, name):
if (ident_class, name) in self.truncated_names:
return self.truncated_names[(ident_class, name)]
anonname = name.apply_map(self.anon_map)
if len(anonname) > self.label_length - 6:
counter = self.truncated_names.get(ident_class, 1)
truncname = (
anonname[0 : max(self.label_length - 6, 0)]
+ "_"
+ hex(counter)[2:]
)
self.truncated_names[ident_class] = counter + 1
else:
truncname = anonname
self.truncated_names[(ident_class, name)] = truncname
return truncname
def _anonymize(self, name):
return name % self.anon_map
def bindparam_string(
self, name, positional_names=None, expanding=False, **kw
):
if self.positional:
if positional_names is not None:
positional_names.append(name)
else:
self.positiontup.append(name)
if expanding:
self.contains_expanding_parameters = True
return "([EXPANDING_%s])" % name
else:
return self.bindtemplate % {"name": name}
def visit_cte(
self,
cte,
asfrom=False,
ashint=False,
fromhints=None,
visiting_cte=None,
**kwargs
):
self._init_cte_state()
kwargs["visiting_cte"] = cte
if isinstance(cte.name, elements._truncated_label):
cte_name = self._truncated_identifier("alias", cte.name)
else:
cte_name = cte.name
is_new_cte = True
embedded_in_current_named_cte = False
if cte_name in self.ctes_by_name:
existing_cte = self.ctes_by_name[cte_name]
embedded_in_current_named_cte = visiting_cte is existing_cte
# we've generated a same-named CTE that we are enclosed in,
# or this is the same CTE. just return the name.
if cte in existing_cte._restates or cte is existing_cte:
is_new_cte = False
elif existing_cte in cte._restates:
# we've generated a same-named CTE that is
# enclosed in us - we take precedence, so
# discard the text for the "inner".
del self.ctes[existing_cte]
else:
raise exc.CompileError(
"Multiple, unrelated CTEs found with "
"the same name: %r" % cte_name
)
if asfrom or is_new_cte:
if cte._cte_alias is not None:
pre_alias_cte = cte._cte_alias
cte_pre_alias_name = cte._cte_alias.name
if isinstance(cte_pre_alias_name, elements._truncated_label):
cte_pre_alias_name = self._truncated_identifier(
"alias", cte_pre_alias_name
)
else:
pre_alias_cte = cte
cte_pre_alias_name = None
if is_new_cte:
self.ctes_by_name[cte_name] = cte
# look for embedded DML ctes and propagate autocommit
if (
"autocommit" in cte.element._execution_options
and "autocommit" not in self.execution_options
):
self.execution_options = self.execution_options.union(
{
"autocommit": cte.element._execution_options[
"autocommit"
]
}
)
if pre_alias_cte not in self.ctes:
self.visit_cte(pre_alias_cte, **kwargs)
if not cte_pre_alias_name and cte not in self.ctes:
if cte.recursive:
self.ctes_recursive = True
text = self.preparer.format_alias(cte, cte_name)
if cte.recursive:
if isinstance(cte.original, selectable.Select):
col_source = cte.original
elif isinstance(cte.original, selectable.CompoundSelect):
col_source = cte.original.selects[0]
else:
assert False
recur_cols = [
c
for c in util.unique_list(col_source.inner_columns)
if c is not None
]
text += "(%s)" % (
", ".join(
self.preparer.format_column(ident)
for ident in recur_cols
)
)
if self.positional:
kwargs["positional_names"] = self.cte_positional[cte] = []
text += " AS %s\n%s" % (
self._generate_prefixes(cte, cte._prefixes, **kwargs),
cte.original._compiler_dispatch(
self, asfrom=True, **kwargs
),
)
if cte._suffixes:
text += " " + self._generate_prefixes(
cte, cte._suffixes, **kwargs
)
self.ctes[cte] = text
if asfrom:
if not is_new_cte and embedded_in_current_named_cte:
return self.preparer.format_alias(cte, cte_name)
if cte_pre_alias_name:
text = self.preparer.format_alias(cte, cte_pre_alias_name)
if self.preparer._requires_quotes(cte_name):
cte_name = self.preparer.quote(cte_name)
text += self.get_render_as_alias_suffix(cte_name)
return text
else:
return self.preparer.format_alias(cte, cte_name)
def visit_alias(
self,
alias,
asfrom=False,
ashint=False,
iscrud=False,
fromhints=None,
**kwargs
):
if asfrom or ashint:
if isinstance(alias.name, elements._truncated_label):
alias_name = self._truncated_identifier("alias", alias.name)
else:
alias_name = alias.name
if ashint:
return self.preparer.format_alias(alias, alias_name)
elif asfrom:
ret = alias.original._compiler_dispatch(
self, asfrom=True, **kwargs
) + self.get_render_as_alias_suffix(
self.preparer.format_alias(alias, alias_name)
)
if fromhints and alias in fromhints:
ret = self.format_from_hint_text(
ret, alias, fromhints[alias], iscrud
)
return ret
else:
return alias.original._compiler_dispatch(self, **kwargs)
def visit_lateral(self, lateral, **kw):
kw["lateral"] = True
return "LATERAL %s" % self.visit_alias(lateral, **kw)
def visit_tablesample(self, tablesample, asfrom=False, **kw):
text = "%s TABLESAMPLE %s" % (
self.visit_alias(tablesample, asfrom=True, **kw),
tablesample._get_method()._compiler_dispatch(self, **kw),
)
if tablesample.seed is not None:
text += " REPEATABLE (%s)" % (
tablesample.seed._compiler_dispatch(self, **kw)
)
return text
def get_render_as_alias_suffix(self, alias_name_text):
return " AS " + alias_name_text
def _add_to_result_map(self, keyname, name, objects, type_):
self._result_columns.append((keyname, name, objects, type_))
def _label_select_column(
self,
select,
column,
populate_result_map,
asfrom,
column_clause_args,
name=None,
within_columns_clause=True,
need_column_expressions=False,
):
"""produce labeled columns present in a select()."""
impl = column.type.dialect_impl(self.dialect)
if impl._has_column_expression and (
need_column_expressions or populate_result_map
):
col_expr = impl.column_expression(column)
if populate_result_map:
def add_to_result_map(keyname, name, objects, type_):
self._add_to_result_map(
keyname, name, (column,) + objects, type_
)
else:
add_to_result_map = None
else:
col_expr = column
if populate_result_map:
add_to_result_map = self._add_to_result_map
else:
add_to_result_map = None
if not within_columns_clause:
result_expr = col_expr
elif isinstance(column, elements.Label):
if col_expr is not column:
result_expr = _CompileLabel(
col_expr, column.name, alt_names=(column.element,)
)
else:
result_expr = col_expr
elif select is not None and name:
result_expr = _CompileLabel(
col_expr, name, alt_names=(column._key_label,)
)
elif (
asfrom
and isinstance(column, elements.ColumnClause)
and not column.is_literal
and column.table is not None
and not isinstance(column.table, selectable.Select)
):
result_expr = _CompileLabel(
col_expr,
elements._as_truncated(column.name),
alt_names=(column.key,),
)
elif (
not isinstance(column, elements.TextClause)
and (
not isinstance(column, elements.UnaryExpression)
or column.wraps_column_expression
)
and (
not hasattr(column, "name")
or isinstance(column, functions.Function)
)
):
result_expr = _CompileLabel(col_expr, column.anon_label)
elif col_expr is not column:
# TODO: are we sure "column" has a .name and .key here ?
# assert isinstance(column, elements.ColumnClause)
result_expr = _CompileLabel(
col_expr,
elements._as_truncated(column.name),
alt_names=(column.key,),
)
else:
result_expr = col_expr
column_clause_args.update(
within_columns_clause=within_columns_clause,
add_to_result_map=add_to_result_map,
)
return result_expr._compiler_dispatch(self, **column_clause_args)
def format_from_hint_text(self, sqltext, table, hint, iscrud):
hinttext = self.get_from_hint_text(table, hint)
if hinttext:
sqltext += " " + hinttext
return sqltext
def get_select_hint_text(self, byfroms):
return None
def get_from_hint_text(self, table, text):
return None
def get_crud_hint_text(self, table, text):
return None
def get_statement_hint_text(self, hint_texts):
return " ".join(hint_texts)
def _transform_select_for_nested_joins(self, select):
"""Rewrite any "a JOIN (b JOIN c)" expression as
"a JOIN (select * from b JOIN c) AS anon", to support
databases that can't parse a parenthesized join correctly
(i.e. sqlite < 3.7.16).
"""
cloned = {}
column_translate = [{}]
def visit(element, **kw):
if element in column_translate[-1]:
return column_translate[-1][element]
elif element in cloned:
return cloned[element]
newelem = cloned[element] = element._clone()
if (
newelem.is_selectable
and newelem._is_join
and isinstance(newelem.right, selectable.FromGrouping)
):
newelem._reset_exported()
newelem.left = visit(newelem.left, **kw)
right = visit(newelem.right, **kw)
selectable_ = selectable.Select(
[right.element], use_labels=True
).alias()
for c in selectable_.c:
c._key_label = c.key
c._label = c.name
translate_dict = dict(
zip(newelem.right.element.c, selectable_.c)
)
# translating from both the old and the new
# because different select() structures will lead us
# to traverse differently
translate_dict[right.element.left] = selectable_
translate_dict[right.element.right] = selectable_
translate_dict[newelem.right.element.left] = selectable_
translate_dict[newelem.right.element.right] = selectable_
# propagate translations that we've gained
# from nested visit(newelem.right) outwards
# to the enclosing select here. this happens
# only when we have more than one level of right
# join nesting, i.e. "a JOIN (b JOIN (c JOIN d))"
for k, v in list(column_translate[-1].items()):
if v in translate_dict:
# remarkably, no current ORM tests (May 2013)
# hit this condition, only test_join_rewriting
# does.
column_translate[-1][k] = translate_dict[v]
column_translate[-1].update(translate_dict)
newelem.right = selectable_
newelem.onclause = visit(newelem.onclause, **kw)
elif newelem._is_from_container:
# if we hit an Alias, CompoundSelect or ScalarSelect, put a
# marker in the stack.
kw["transform_clue"] = "select_container"
newelem._copy_internals(clone=visit, **kw)
elif newelem.is_selectable and newelem._is_select:
barrier_select = (
kw.get("transform_clue", None) == "select_container"
)
# if we're still descended from an
# Alias/CompoundSelect/ScalarSelect, we're
# in a FROM clause, so start with a new translate collection
if barrier_select:
column_translate.append({})
kw["transform_clue"] = "inside_select"
newelem._copy_internals(clone=visit, **kw)
if barrier_select:
del column_translate[-1]
else:
newelem._copy_internals(clone=visit, **kw)
return newelem
return visit(select)
def _transform_result_map_for_nested_joins(
self, select, transformed_select
):
inner_col = dict(
(c._key_label, c) for c in transformed_select.inner_columns
)
d = dict((inner_col[c._key_label], c) for c in select.inner_columns)
self._result_columns = [
(key, name, tuple([d.get(col, col) for col in objs]), typ)
for key, name, objs, typ in self._result_columns
]
_default_stack_entry = util.immutabledict(
[("correlate_froms", frozenset()), ("asfrom_froms", frozenset())]
)
def _display_froms_for_select(self, select, asfrom, lateral=False):
# utility method to help external dialects
# get the correct from list for a select.
# specifically the oracle dialect needs this feature
# right now.
toplevel = not self.stack
entry = self._default_stack_entry if toplevel else self.stack[-1]
correlate_froms = entry["correlate_froms"]
asfrom_froms = entry["asfrom_froms"]
if asfrom and not lateral:
froms = select._get_display_froms(
explicit_correlate_froms=correlate_froms.difference(
asfrom_froms
),
implicit_correlate_froms=(),
)
else:
froms = select._get_display_froms(
explicit_correlate_froms=correlate_froms,
implicit_correlate_froms=asfrom_froms,
)
return froms
def visit_select(
self,
select,
asfrom=False,
parens=True,
fromhints=None,
compound_index=0,
nested_join_translation=False,
select_wraps_for=None,
lateral=False,
**kwargs
):
needs_nested_translation = (
select.use_labels
and not nested_join_translation
and not self.stack
and not self.dialect.supports_right_nested_joins
)
if needs_nested_translation:
transformed_select = self._transform_select_for_nested_joins(
select
)
text = self.visit_select(
transformed_select,
asfrom=asfrom,
parens=parens,
fromhints=fromhints,
compound_index=compound_index,
nested_join_translation=True,
**kwargs
)
toplevel = not self.stack
entry = self._default_stack_entry if toplevel else self.stack[-1]
populate_result_map = need_column_expressions = (
toplevel
or entry.get("need_result_map_for_compound", False)
or entry.get("need_result_map_for_nested", False)
)
if compound_index > 0:
populate_result_map = False
# this was first proposed as part of #3372; however, it is not
# reached in current tests and could possibly be an assertion
# instead.
if not populate_result_map and "add_to_result_map" in kwargs:
del kwargs["add_to_result_map"]
if needs_nested_translation:
if populate_result_map:
self._transform_result_map_for_nested_joins(
select, transformed_select
)
return text
froms = self._setup_select_stack(select, entry, asfrom, lateral)
column_clause_args = kwargs.copy()
column_clause_args.update(
{"within_label_clause": False, "within_columns_clause": False}
)
text = "SELECT " # we're off to a good start !
if select._hints:
hint_text, byfrom = self._setup_select_hints(select)
if hint_text:
text += hint_text + " "
else:
byfrom = None
if select._prefixes:
text += self._generate_prefixes(select, select._prefixes, **kwargs)
text += self.get_select_precolumns(select, **kwargs)
# the actual list of columns to print in the SELECT column list.
inner_columns = [
c
for c in [
self._label_select_column(
select,
column,
populate_result_map,
asfrom,
column_clause_args,
name=name,
need_column_expressions=need_column_expressions,
)
for name, column in select._columns_plus_names
]
if c is not None
]
if populate_result_map and select_wraps_for is not None:
# if this select is a compiler-generated wrapper,
# rewrite the targeted columns in the result map
translate = dict(
zip(
[name for (key, name) in select._columns_plus_names],
[
name
for (key, name) in select_wraps_for._columns_plus_names
],
)
)
self._result_columns = [
(key, name, tuple(translate.get(o, o) for o in obj), type_)
for key, name, obj, type_ in self._result_columns
]
text = self._compose_select_body(
text, select, inner_columns, froms, byfrom, kwargs
)
if select._statement_hints:
per_dialect = [
ht
for (dialect_name, ht) in select._statement_hints
if dialect_name in ("*", self.dialect.name)
]
if per_dialect:
text += " " + self.get_statement_hint_text(per_dialect)
if self.ctes and toplevel:
text = self._render_cte_clause() + text
if select._suffixes:
text += " " + self._generate_prefixes(
select, select._suffixes, **kwargs
)
self.stack.pop(-1)
if (asfrom or lateral) and parens:
return "(" + text + ")"
else:
return text
def _setup_select_hints(self, select):
byfrom = dict(
[
(
from_,
hinttext
% {"name": from_._compiler_dispatch(self, ashint=True)},
)
for (from_, dialect), hinttext in select._hints.items()
if dialect in ("*", self.dialect.name)
]
)
hint_text = self.get_select_hint_text(byfrom)
return hint_text, byfrom
def _setup_select_stack(self, select, entry, asfrom, lateral):
correlate_froms = entry["correlate_froms"]
asfrom_froms = entry["asfrom_froms"]
if asfrom and not lateral:
froms = select._get_display_froms(
explicit_correlate_froms=correlate_froms.difference(
asfrom_froms
),
implicit_correlate_froms=(),
)
else:
froms = select._get_display_froms(
explicit_correlate_froms=correlate_froms,
implicit_correlate_froms=asfrom_froms,
)
new_correlate_froms = set(selectable._from_objects(*froms))
all_correlate_froms = new_correlate_froms.union(correlate_froms)
new_entry = {
"asfrom_froms": new_correlate_froms,
"correlate_froms": all_correlate_froms,
"selectable": select,
}
self.stack.append(new_entry)
return froms
def _compose_select_body(
self, text, select, inner_columns, froms, byfrom, kwargs
):
text += ", ".join(inner_columns)
if froms:
text += " \nFROM "
if select._hints:
text += ", ".join(
[
f._compiler_dispatch(
self, asfrom=True, fromhints=byfrom, **kwargs
)
for f in froms
]
)
else:
text += ", ".join(
[
f._compiler_dispatch(self, asfrom=True, **kwargs)
for f in froms
]
)
else:
text += self.default_from()
if select._whereclause is not None:
t = select._whereclause._compiler_dispatch(self, **kwargs)
if t:
text += " \nWHERE " + t
if select._group_by_clause.clauses:
text += self.group_by_clause(select, **kwargs)
if select._having is not None:
t = select._having._compiler_dispatch(self, **kwargs)
if t:
text += " \nHAVING " + t
if select._order_by_clause.clauses:
text += self.order_by_clause(select, **kwargs)
if (
select._limit_clause is not None
or select._offset_clause is not None
):
text += self.limit_clause(select, **kwargs)
if select._for_update_arg is not None:
text += self.for_update_clause(select, **kwargs)
return text
def _generate_prefixes(self, stmt, prefixes, **kw):
clause = " ".join(
prefix._compiler_dispatch(self, **kw)
for prefix, dialect_name in prefixes
if dialect_name is None or dialect_name == self.dialect.name
)
if clause:
clause += " "
return clause
def _render_cte_clause(self):
if self.positional:
self.positiontup = (
sum([self.cte_positional[cte] for cte in self.ctes], [])
+ self.positiontup
)
cte_text = self.get_cte_preamble(self.ctes_recursive) + " "
cte_text += ", \n".join([txt for txt in self.ctes.values()])
cte_text += "\n "
return cte_text
def get_cte_preamble(self, recursive):
if recursive:
return "WITH RECURSIVE"
else:
return "WITH"
def get_select_precolumns(self, select, **kw):
"""Called when building a ``SELECT`` statement, position is just
before column list.
"""
return select._distinct and "DISTINCT " or ""
def group_by_clause(self, select, **kw):
"""allow dialects to customize how GROUP BY is rendered."""
group_by = select._group_by_clause._compiler_dispatch(self, **kw)
if group_by:
return " GROUP BY " + group_by
else:
return ""
def order_by_clause(self, select, **kw):
"""allow dialects to customize how ORDER BY is rendered."""
order_by = select._order_by_clause._compiler_dispatch(self, **kw)
if order_by:
return " ORDER BY " + order_by
else:
return ""
def for_update_clause(self, select, **kw):
return " FOR UPDATE"
def returning_clause(self, stmt, returning_cols):
raise exc.CompileError(
"RETURNING is not supported by this "
"dialect's statement compiler."
)
def limit_clause(self, select, **kw):
text = ""
if select._limit_clause is not None:
text += "\n LIMIT " + self.process(select._limit_clause, **kw)
if select._offset_clause is not None:
if select._limit_clause is None:
text += "\n LIMIT -1"
text += " OFFSET " + self.process(select._offset_clause, **kw)
return text
def visit_table(
self,
table,
asfrom=False,
iscrud=False,
ashint=False,
fromhints=None,
use_schema=True,
**kwargs
):
if asfrom or ashint:
effective_schema = self.preparer.schema_for_object(table)
if use_schema and effective_schema:
ret = (
self.preparer.quote_schema(effective_schema)
+ "."
+ self.preparer.quote(table.name)
)
else:
ret = self.preparer.quote(table.name)
if fromhints and table in fromhints:
ret = self.format_from_hint_text(
ret, table, fromhints[table], iscrud
)
return ret
else:
return ""
def visit_join(self, join, asfrom=False, **kwargs):
if join.full:
join_type = " FULL OUTER JOIN "
elif join.isouter:
join_type = " LEFT OUTER JOIN "
else:
join_type = " JOIN "
return (
join.left._compiler_dispatch(self, asfrom=True, **kwargs)
+ join_type
+ join.right._compiler_dispatch(self, asfrom=True, **kwargs)
+ " ON "
+ join.onclause._compiler_dispatch(self, **kwargs)
)
def _setup_crud_hints(self, stmt, table_text):
dialect_hints = dict(
[
(table, hint_text)
for (table, dialect), hint_text in stmt._hints.items()
if dialect in ("*", self.dialect.name)
]
)
if stmt.table in dialect_hints:
table_text = self.format_from_hint_text(
table_text, stmt.table, dialect_hints[stmt.table], True
)
return dialect_hints, table_text
def visit_insert(self, insert_stmt, asfrom=False, **kw):
toplevel = not self.stack
self.stack.append(
{
"correlate_froms": set(),
"asfrom_froms": set(),
"selectable": insert_stmt,
}
)
crud_params = crud._setup_crud_params(
self, insert_stmt, crud.ISINSERT, **kw
)
if (
not crud_params
and not self.dialect.supports_default_values
and not self.dialect.supports_empty_insert
):
raise exc.CompileError(
"The '%s' dialect with current database "
"version settings does not support empty "
"inserts." % self.dialect.name
)
if insert_stmt._has_multi_parameters:
if not self.dialect.supports_multivalues_insert:
raise exc.CompileError(
"The '%s' dialect with current database "
"version settings does not support "
"in-place multirow inserts." % self.dialect.name
)
crud_params_single = crud_params[0]
else:
crud_params_single = crud_params
preparer = self.preparer
supports_default_values = self.dialect.supports_default_values
text = "INSERT "
if insert_stmt._prefixes:
text += self._generate_prefixes(
insert_stmt, insert_stmt._prefixes, **kw
)
text += "INTO "
table_text = preparer.format_table(insert_stmt.table)
if insert_stmt._hints:
_, table_text = self._setup_crud_hints(insert_stmt, table_text)
text += table_text
if crud_params_single or not supports_default_values:
text += " (%s)" % ", ".join(
[preparer.format_column(c[0]) for c in crud_params_single]
)
if self.returning or insert_stmt._returning:
returning_clause = self.returning_clause(
insert_stmt, self.returning or insert_stmt._returning
)
if self.returning_precedes_values:
text += " " + returning_clause
else:
returning_clause = None
if insert_stmt.select is not None:
select_text = self.process(self._insert_from_select, **kw)
if self.ctes and toplevel and self.dialect.cte_follows_insert:
text += " %s%s" % (self._render_cte_clause(), select_text)
else:
text += " %s" % select_text
elif not crud_params and supports_default_values:
text += " DEFAULT VALUES"
elif insert_stmt._has_multi_parameters:
text += " VALUES %s" % (
", ".join(
"(%s)" % (", ".join(c[1] for c in crud_param_set))
for crud_param_set in crud_params
)
)
else:
insert_single_values_expr = ", ".join([c[1] for c in crud_params])
text += " VALUES (%s)" % insert_single_values_expr
if toplevel:
self.insert_single_values_expr = insert_single_values_expr
if insert_stmt._post_values_clause is not None:
post_values_clause = self.process(
insert_stmt._post_values_clause, **kw
)
if post_values_clause:
text += " " + post_values_clause
if returning_clause and not self.returning_precedes_values:
text += " " + returning_clause
if self.ctes and toplevel and not self.dialect.cte_follows_insert:
text = self._render_cte_clause() + text
self.stack.pop(-1)
if asfrom:
return "(" + text + ")"
else:
return text
def update_limit_clause(self, update_stmt):
"""Provide a hook for MySQL to add LIMIT to the UPDATE"""
return None
def update_tables_clause(self, update_stmt, from_table, extra_froms, **kw):
"""Provide a hook to override the initial table clause
in an UPDATE statement.
MySQL overrides this.
"""
kw["asfrom"] = True
return from_table._compiler_dispatch(self, iscrud=True, **kw)
def update_from_clause(
self, update_stmt, from_table, extra_froms, from_hints, **kw
):
"""Provide a hook to override the generation of an
UPDATE..FROM clause.
MySQL and MSSQL override this.
"""
raise NotImplementedError(
"This backend does not support multiple-table "
"criteria within UPDATE"
)
def visit_update(self, update_stmt, asfrom=False, **kw):
toplevel = not self.stack
extra_froms = update_stmt._extra_froms
is_multitable = bool(extra_froms)
if is_multitable:
# main table might be a JOIN
main_froms = set(selectable._from_objects(update_stmt.table))
render_extra_froms = [
f for f in extra_froms if f not in main_froms
]
correlate_froms = main_froms.union(extra_froms)
else:
render_extra_froms = []
correlate_froms = {update_stmt.table}
self.stack.append(
{
"correlate_froms": correlate_froms,
"asfrom_froms": correlate_froms,
"selectable": update_stmt,
}
)
text = "UPDATE "
if update_stmt._prefixes:
text += self._generate_prefixes(
update_stmt, update_stmt._prefixes, **kw
)
table_text = self.update_tables_clause(
update_stmt, update_stmt.table, render_extra_froms, **kw
)
crud_params = crud._setup_crud_params(
self, update_stmt, crud.ISUPDATE, **kw
)
if update_stmt._hints:
dialect_hints, table_text = self._setup_crud_hints(
update_stmt, table_text
)
else:
dialect_hints = None
text += table_text
text += " SET "
include_table = (
is_multitable and self.render_table_with_column_in_update_from
)
text += ", ".join(
c[0]._compiler_dispatch(self, include_table=include_table)
+ "="
+ c[1]
for c in crud_params
)
if self.returning or update_stmt._returning:
if self.returning_precedes_values:
text += " " + self.returning_clause(
update_stmt, self.returning or update_stmt._returning
)
if extra_froms:
extra_from_text = self.update_from_clause(
update_stmt,
update_stmt.table,
render_extra_froms,
dialect_hints,
**kw
)
if extra_from_text:
text += " " + extra_from_text
if update_stmt._whereclause is not None:
t = self.process(update_stmt._whereclause, **kw)
if t:
text += " WHERE " + t
limit_clause = self.update_limit_clause(update_stmt)
if limit_clause:
text += " " + limit_clause
if (
self.returning or update_stmt._returning
) and not self.returning_precedes_values:
text += " " + self.returning_clause(
update_stmt, self.returning or update_stmt._returning
)
if self.ctes and toplevel:
text = self._render_cte_clause() + text
self.stack.pop(-1)
if asfrom:
return "(" + text + ")"
else:
return text
@util.memoized_property
def _key_getters_for_crud_column(self):
return crud._key_getters_for_crud_column(self, self.statement)
def delete_extra_from_clause(
self, update_stmt, from_table, extra_froms, from_hints, **kw
):
"""Provide a hook to override the generation of an
DELETE..FROM clause.
This can be used to implement DELETE..USING for example.
MySQL and MSSQL override this.
"""
raise NotImplementedError(
"This backend does not support multiple-table "
"criteria within DELETE"
)
def delete_table_clause(self, delete_stmt, from_table, extra_froms):
return from_table._compiler_dispatch(self, asfrom=True, iscrud=True)
def visit_delete(self, delete_stmt, asfrom=False, **kw):
toplevel = not self.stack
crud._setup_crud_params(self, delete_stmt, crud.ISDELETE, **kw)
extra_froms = delete_stmt._extra_froms
correlate_froms = {delete_stmt.table}.union(extra_froms)
self.stack.append(
{
"correlate_froms": correlate_froms,
"asfrom_froms": correlate_froms,
"selectable": delete_stmt,
}
)
text = "DELETE "
if delete_stmt._prefixes:
text += self._generate_prefixes(
delete_stmt, delete_stmt._prefixes, **kw
)
text += "FROM "
table_text = self.delete_table_clause(
delete_stmt, delete_stmt.table, extra_froms
)
if delete_stmt._hints:
dialect_hints, table_text = self._setup_crud_hints(
delete_stmt, table_text
)
else:
dialect_hints = None
text += table_text
if delete_stmt._returning:
if self.returning_precedes_values:
text += " " + self.returning_clause(
delete_stmt, delete_stmt._returning
)
if extra_froms:
extra_from_text = self.delete_extra_from_clause(
delete_stmt,
delete_stmt.table,
extra_froms,
dialect_hints,
**kw
)
if extra_from_text:
text += " " + extra_from_text
if delete_stmt._whereclause is not None:
t = delete_stmt._whereclause._compiler_dispatch(self, **kw)
if t:
text += " WHERE " + t
if delete_stmt._returning and not self.returning_precedes_values:
text += " " + self.returning_clause(
delete_stmt, delete_stmt._returning
)
if self.ctes and toplevel:
text = self._render_cte_clause() + text
self.stack.pop(-1)
if asfrom:
return "(" + text + ")"
else:
return text
def visit_savepoint(self, savepoint_stmt):
return "SAVEPOINT %s" % self.preparer.format_savepoint(savepoint_stmt)
def visit_rollback_to_savepoint(self, savepoint_stmt):
return "ROLLBACK TO SAVEPOINT %s" % self.preparer.format_savepoint(
savepoint_stmt
)
def visit_release_savepoint(self, savepoint_stmt):
return "RELEASE SAVEPOINT %s" % self.preparer.format_savepoint(
savepoint_stmt
)
class StrSQLCompiler(SQLCompiler):
"""A :class:`.SQLCompiler` subclass which allows a small selection
of non-standard SQL features to render into a string value.
The :class:`.StrSQLCompiler` is invoked whenever a Core expression
element is directly stringified without calling upon the
:meth:`_expression.ClauseElement.compile` method.
It can render a limited set
of non-standard SQL constructs to assist in basic stringification,
however for more substantial custom or dialect-specific SQL constructs,
it will be necessary to make use of
:meth:`_expression.ClauseElement.compile`
directly.
.. seealso::
:ref:`faq_sql_expression_string`
"""
def _fallback_column_name(self, column):
return ""
def visit_getitem_binary(self, binary, operator, **kw):
return "%s[%s]" % (
self.process(binary.left, **kw),
self.process(binary.right, **kw),
)
def visit_json_getitem_op_binary(self, binary, operator, **kw):
return self.visit_getitem_binary(binary, operator, **kw)
def visit_json_path_getitem_op_binary(self, binary, operator, **kw):
return self.visit_getitem_binary(binary, operator, **kw)
def visit_sequence(self, seq, **kw):
return "" % self.preparer.format_sequence(seq)
def returning_clause(self, stmt, returning_cols):
columns = [
self._label_select_column(None, c, True, False, {})
for c in elements._select_iterables(returning_cols)
]
return "RETURNING " + ", ".join(columns)
def update_from_clause(
self, update_stmt, from_table, extra_froms, from_hints, **kw
):
return "FROM " + ", ".join(
t._compiler_dispatch(self, asfrom=True, fromhints=from_hints, **kw)
for t in extra_froms
)
def delete_extra_from_clause(
self, update_stmt, from_table, extra_froms, from_hints, **kw
):
return ", " + ", ".join(
t._compiler_dispatch(self, asfrom=True, fromhints=from_hints, **kw)
for t in extra_froms
)
def get_from_hint_text(self, table, text):
return "[%s]" % text
class DDLCompiler(Compiled):
@util.memoized_property
def sql_compiler(self):
return self.dialect.statement_compiler(
self.dialect, None, schema_translate_map=self.schema_translate_map
)
@util.memoized_property
def type_compiler(self):
return self.dialect.type_compiler
def construct_params(self, params=None):
return None
def visit_ddl(self, ddl, **kwargs):
# table events can substitute table and schema name
context = ddl.context
if isinstance(ddl.target, schema.Table):
context = context.copy()
preparer = self.preparer
path = preparer.format_table_seq(ddl.target)
if len(path) == 1:
table, sch = path[0], ""
else:
table, sch = path[-1], path[0]
context.setdefault("table", table)
context.setdefault("schema", sch)
context.setdefault("fullname", preparer.format_table(ddl.target))
return self.sql_compiler.post_process_text(ddl.statement % context)
def visit_create_schema(self, create):
schema = self.preparer.format_schema(create.element)
return "CREATE SCHEMA " + schema
def visit_drop_schema(self, drop):
schema = self.preparer.format_schema(drop.element)
text = "DROP SCHEMA " + schema
if drop.cascade:
text += " CASCADE"
return text
def visit_create_table(self, create):
table = create.element
preparer = self.preparer
text = "\nCREATE "
if table._prefixes:
text += " ".join(table._prefixes) + " "
text += "TABLE " + preparer.format_table(table) + " "
create_table_suffix = self.create_table_suffix(table)
if create_table_suffix:
text += create_table_suffix + " "
text += "("
separator = "\n"
# if only one primary key, specify it along with the column
first_pk = False
for create_column in create.columns:
column = create_column.element
try:
processed = self.process(
create_column, first_pk=column.primary_key and not first_pk
)
if processed is not None:
text += separator
separator = ", \n"
text += "\t" + processed
if column.primary_key:
first_pk = True
except exc.CompileError as ce:
util.raise_(
exc.CompileError(
util.u("(in table '%s', column '%s'): %s")
% (table.description, column.name, ce.args[0])
),
from_=ce,
)
const = self.create_table_constraints(
table,
_include_foreign_key_constraints=create.include_foreign_key_constraints, # noqa
)
if const:
text += separator + "\t" + const
text += "\n)%s\n\n" % self.post_create_table(table)
return text
def visit_create_column(self, create, first_pk=False):
column = create.element
if column.system:
return None
text = self.get_column_specification(column, first_pk=first_pk)
const = " ".join(
self.process(constraint) for constraint in column.constraints
)
if const:
text += " " + const
return text
def create_table_constraints(
self, table, _include_foreign_key_constraints=None
):
# On some DB order is significant: visit PK first, then the
# other constraints (engine.ReflectionTest.testbasic failed on FB2)
constraints = []
if table.primary_key:
constraints.append(table.primary_key)
all_fkcs = table.foreign_key_constraints
if _include_foreign_key_constraints is not None:
omit_fkcs = all_fkcs.difference(_include_foreign_key_constraints)
else:
omit_fkcs = set()
constraints.extend(
[
c
for c in table._sorted_constraints
if c is not table.primary_key and c not in omit_fkcs
]
)
return ", \n\t".join(
p
for p in (
self.process(constraint)
for constraint in constraints
if (
constraint._create_rule is None
or constraint._create_rule(self)
)
and (
not self.dialect.supports_alter
or not getattr(constraint, "use_alter", False)
)
)
if p is not None
)
def visit_drop_table(self, drop):
return "\nDROP TABLE " + self.preparer.format_table(drop.element)
def visit_drop_view(self, drop):
return "\nDROP VIEW " + self.preparer.format_table(drop.element)
def _verify_index_table(self, index):
if index.table is None:
raise exc.CompileError(
"Index '%s' is not associated " "with any table." % index.name
)
def visit_create_index(
self, create, include_schema=False, include_table_schema=True
):
index = create.element
self._verify_index_table(index)
preparer = self.preparer
text = "CREATE "
if index.unique:
text += "UNIQUE "
if index.name is None:
raise exc.CompileError(
"CREATE INDEX requires that the index have a name"
)
text += "INDEX %s ON %s (%s)" % (
self._prepared_index_name(index, include_schema=include_schema),
preparer.format_table(
index.table, use_schema=include_table_schema
),
", ".join(
self.sql_compiler.process(
expr, include_table=False, literal_binds=True
)
for expr in index.expressions
),
)
return text
def visit_drop_index(self, drop):
index = drop.element
if index.name is None:
raise exc.CompileError(
"DROP INDEX requires that the index have a name"
)
return "\nDROP INDEX " + self._prepared_index_name(
index, include_schema=True
)
def _prepared_index_name(self, index, include_schema=False):
if index.table is not None:
effective_schema = self.preparer.schema_for_object(index.table)
else:
effective_schema = None
if include_schema and effective_schema:
schema_name = self.preparer.quote_schema(effective_schema)
else:
schema_name = None
index_name = self.preparer.format_index(index)
if schema_name:
index_name = schema_name + "." + index_name
return index_name
def visit_add_constraint(self, create):
return "ALTER TABLE %s ADD %s" % (
self.preparer.format_table(create.element.table),
self.process(create.element),
)
def visit_set_table_comment(self, create):
return "COMMENT ON TABLE %s IS %s" % (
self.preparer.format_table(create.element),
self.sql_compiler.render_literal_value(
create.element.comment, sqltypes.String()
),
)
def visit_drop_table_comment(self, drop):
return "COMMENT ON TABLE %s IS NULL" % self.preparer.format_table(
drop.element
)
def visit_set_column_comment(self, create):
return "COMMENT ON COLUMN %s IS %s" % (
self.preparer.format_column(
create.element, use_table=True, use_schema=True
),
self.sql_compiler.render_literal_value(
create.element.comment, sqltypes.String()
),
)
def visit_drop_column_comment(self, drop):
return "COMMENT ON COLUMN %s IS NULL" % self.preparer.format_column(
drop.element, use_table=True
)
def visit_create_sequence(self, create):
text = "CREATE SEQUENCE %s" % self.preparer.format_sequence(
create.element
)
if create.element.increment is not None:
text += " INCREMENT BY %d" % create.element.increment
if create.element.start is not None:
text += " START WITH %d" % create.element.start
if create.element.minvalue is not None:
text += " MINVALUE %d" % create.element.minvalue
if create.element.maxvalue is not None:
text += " MAXVALUE %d" % create.element.maxvalue
if create.element.nominvalue is not None:
text += " NO MINVALUE"
if create.element.nomaxvalue is not None:
text += " NO MAXVALUE"
if create.element.cache is not None:
text += " CACHE %d" % create.element.cache
if create.element.order is True:
text += " ORDER"
if create.element.cycle is not None:
text += " CYCLE"
return text
def visit_drop_sequence(self, drop):
return "DROP SEQUENCE %s" % self.preparer.format_sequence(drop.element)
def visit_drop_constraint(self, drop):
constraint = drop.element
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
else:
formatted_name = None
if formatted_name is None:
raise exc.CompileError(
"Can't emit DROP CONSTRAINT for constraint %r; "
"it has no name" % drop.element
)
return "ALTER TABLE %s DROP CONSTRAINT %s%s" % (
self.preparer.format_table(drop.element.table),
formatted_name,
drop.cascade and " CASCADE" or "",
)
def get_column_specification(self, column, **kwargs):
colspec = (
self.preparer.format_column(column)
+ " "
+ self.dialect.type_compiler.process(
column.type, type_expression=column
)
)
default = self.get_column_default_string(column)
if default is not None:
colspec += " DEFAULT " + default
if column.computed is not None:
colspec += " " + self.process(column.computed)
if not column.nullable:
colspec += " NOT NULL"
return colspec
def create_table_suffix(self, table):
return ""
def post_create_table(self, table):
return ""
def get_column_default_string(self, column):
if isinstance(column.server_default, schema.DefaultClause):
if isinstance(column.server_default.arg, util.string_types):
return self.sql_compiler.render_literal_value(
column.server_default.arg, sqltypes.STRINGTYPE
)
else:
return self.sql_compiler.process(
column.server_default.arg, literal_binds=True
)
else:
return None
def visit_check_constraint(self, constraint):
text = ""
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
if formatted_name is not None:
text += "CONSTRAINT %s " % formatted_name
text += "CHECK (%s)" % self.sql_compiler.process(
constraint.sqltext, include_table=False, literal_binds=True
)
text += self.define_constraint_deferrability(constraint)
return text
def visit_column_check_constraint(self, constraint):
text = ""
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
if formatted_name is not None:
text += "CONSTRAINT %s " % formatted_name
text += "CHECK (%s)" % self.sql_compiler.process(
constraint.sqltext, include_table=False, literal_binds=True
)
text += self.define_constraint_deferrability(constraint)
return text
def visit_primary_key_constraint(self, constraint):
if len(constraint) == 0:
return ""
text = ""
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
if formatted_name is not None:
text += "CONSTRAINT %s " % formatted_name
text += "PRIMARY KEY "
text += "(%s)" % ", ".join(
self.preparer.quote(c.name)
for c in (
constraint.columns_autoinc_first
if constraint._implicit_generated
else constraint.columns
)
)
text += self.define_constraint_deferrability(constraint)
return text
def visit_foreign_key_constraint(self, constraint):
preparer = self.preparer
text = ""
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
if formatted_name is not None:
text += "CONSTRAINT %s " % formatted_name
remote_table = list(constraint.elements)[0].column.table
text += "FOREIGN KEY(%s) REFERENCES %s (%s)" % (
", ".join(
preparer.quote(f.parent.name) for f in constraint.elements
),
self.define_constraint_remote_table(
constraint, remote_table, preparer
),
", ".join(
preparer.quote(f.column.name) for f in constraint.elements
),
)
text += self.define_constraint_match(constraint)
text += self.define_constraint_cascades(constraint)
text += self.define_constraint_deferrability(constraint)
return text
def define_constraint_remote_table(self, constraint, table, preparer):
"""Format the remote table clause of a CREATE CONSTRAINT clause."""
return preparer.format_table(table)
def visit_unique_constraint(self, constraint):
if len(constraint) == 0:
return ""
text = ""
if constraint.name is not None:
formatted_name = self.preparer.format_constraint(constraint)
if formatted_name is not None:
text += "CONSTRAINT %s " % formatted_name
text += "UNIQUE (%s)" % (
", ".join(self.preparer.quote(c.name) for c in constraint)
)
text += self.define_constraint_deferrability(constraint)
return text
def define_constraint_cascades(self, constraint):
text = ""
if constraint.ondelete is not None:
text += " ON DELETE %s" % self.preparer.validate_sql_phrase(
constraint.ondelete, FK_ON_DELETE
)
if constraint.onupdate is not None:
text += " ON UPDATE %s" % self.preparer.validate_sql_phrase(
constraint.onupdate, FK_ON_UPDATE
)
return text
def define_constraint_deferrability(self, constraint):
text = ""
if constraint.deferrable is not None:
if constraint.deferrable:
text += " DEFERRABLE"
else:
text += " NOT DEFERRABLE"
if constraint.initially is not None:
text += " INITIALLY %s" % self.preparer.validate_sql_phrase(
constraint.initially, FK_INITIALLY
)
return text
def define_constraint_match(self, constraint):
text = ""
if constraint.match is not None:
text += " MATCH %s" % constraint.match
return text
def visit_computed_column(self, generated):
text = "GENERATED ALWAYS AS (%s)" % self.sql_compiler.process(
generated.sqltext, include_table=False, literal_binds=True
)
if generated.persisted is True:
text += " STORED"
elif generated.persisted is False:
text += " VIRTUAL"
return text
class GenericTypeCompiler(TypeCompiler):
def visit_FLOAT(self, type_, **kw):
return "FLOAT"
def visit_REAL(self, type_, **kw):
return "REAL"
def visit_NUMERIC(self, type_, **kw):
if type_.precision is None:
return "NUMERIC"
elif type_.scale is None:
return "NUMERIC(%(precision)s)" % {"precision": type_.precision}
else:
return "NUMERIC(%(precision)s, %(scale)s)" % {
"precision": type_.precision,
"scale": type_.scale,
}
def visit_DECIMAL(self, type_, **kw):
if type_.precision is None:
return "DECIMAL"
elif type_.scale is None:
return "DECIMAL(%(precision)s)" % {"precision": type_.precision}
else:
return "DECIMAL(%(precision)s, %(scale)s)" % {
"precision": type_.precision,
"scale": type_.scale,
}
def visit_INTEGER(self, type_, **kw):
return "INTEGER"
def visit_SMALLINT(self, type_, **kw):
return "SMALLINT"
def visit_BIGINT(self, type_, **kw):
return "BIGINT"
def visit_TIMESTAMP(self, type_, **kw):
return "TIMESTAMP"
def visit_DATETIME(self, type_, **kw):
return "DATETIME"
def visit_DATE(self, type_, **kw):
return "DATE"
def visit_TIME(self, type_, **kw):
return "TIME"
def visit_CLOB(self, type_, **kw):
return "CLOB"
def visit_NCLOB(self, type_, **kw):
return "NCLOB"
def _render_string_type(self, type_, name):
text = name
if type_.length:
text += "(%d)" % type_.length
if type_.collation:
text += ' COLLATE "%s"' % type_.collation
return text
def visit_CHAR(self, type_, **kw):
return self._render_string_type(type_, "CHAR")
def visit_NCHAR(self, type_, **kw):
return self._render_string_type(type_, "NCHAR")
def visit_VARCHAR(self, type_, **kw):
return self._render_string_type(type_, "VARCHAR")
def visit_NVARCHAR(self, type_, **kw):
return self._render_string_type(type_, "NVARCHAR")
def visit_TEXT(self, type_, **kw):
return self._render_string_type(type_, "TEXT")
def visit_BLOB(self, type_, **kw):
return "BLOB"
def visit_BINARY(self, type_, **kw):
return "BINARY" + (type_.length and "(%d)" % type_.length or "")
def visit_VARBINARY(self, type_, **kw):
return "VARBINARY" + (type_.length and "(%d)" % type_.length or "")
def visit_BOOLEAN(self, type_, **kw):
return "BOOLEAN"
def visit_large_binary(self, type_, **kw):
return self.visit_BLOB(type_, **kw)
def visit_boolean(self, type_, **kw):
return self.visit_BOOLEAN(type_, **kw)
def visit_time(self, type_, **kw):
return self.visit_TIME(type_, **kw)
def visit_datetime(self, type_, **kw):
return self.visit_DATETIME(type_, **kw)
def visit_date(self, type_, **kw):
return self.visit_DATE(type_, **kw)
def visit_big_integer(self, type_, **kw):
return self.visit_BIGINT(type_, **kw)
def visit_small_integer(self, type_, **kw):
return self.visit_SMALLINT(type_, **kw)
def visit_integer(self, type_, **kw):
return self.visit_INTEGER(type_, **kw)
def visit_real(self, type_, **kw):
return self.visit_REAL(type_, **kw)
def visit_float(self, type_, **kw):
return self.visit_FLOAT(type_, **kw)
def visit_numeric(self, type_, **kw):
return self.visit_NUMERIC(type_, **kw)
def visit_string(self, type_, **kw):
return self.visit_VARCHAR(type_, **kw)
def visit_unicode(self, type_, **kw):
return self.visit_VARCHAR(type_, **kw)
def visit_text(self, type_, **kw):
return self.visit_TEXT(type_, **kw)
def visit_unicode_text(self, type_, **kw):
return self.visit_TEXT(type_, **kw)
def visit_enum(self, type_, **kw):
return self.visit_VARCHAR(type_, **kw)
def visit_null(self, type_, **kw):
raise exc.CompileError(
"Can't generate DDL for %r; "
"did you forget to specify a "
"type on this Column?" % type_
)
def visit_type_decorator(self, type_, **kw):
return self.process(type_.type_engine(self.dialect), **kw)
def visit_user_defined(self, type_, **kw):
return type_.get_col_spec(**kw)
class StrSQLTypeCompiler(GenericTypeCompiler):
def __getattr__(self, key):
if key.startswith("visit_"):
return self._visit_unknown
else:
raise AttributeError(key)
def _visit_unknown(self, type_, **kw):
return "%s" % type_.__class__.__name__
class IdentifierPreparer(object):
"""Handle quoting and case-folding of identifiers based on options."""
reserved_words = RESERVED_WORDS
legal_characters = LEGAL_CHARACTERS
illegal_initial_characters = ILLEGAL_INITIAL_CHARACTERS
schema_for_object = schema._schema_getter(None)
def __init__(
self,
dialect,
initial_quote='"',
final_quote=None,
escape_quote='"',
quote_case_sensitive_collations=True,
omit_schema=False,
):
"""Construct a new ``IdentifierPreparer`` object.
initial_quote
Character that begins a delimited identifier.
final_quote
Character that ends a delimited identifier. Defaults to
`initial_quote`.
omit_schema
Prevent prepending schema name. Useful for databases that do
not support schemae.
"""
self.dialect = dialect
self.initial_quote = initial_quote
self.final_quote = final_quote or self.initial_quote
self.escape_quote = escape_quote
self.escape_to_quote = self.escape_quote * 2
self.omit_schema = omit_schema
self.quote_case_sensitive_collations = quote_case_sensitive_collations
self._strings = {}
self._double_percents = self.dialect.paramstyle in (
"format",
"pyformat",
)
def _with_schema_translate(self, schema_translate_map):
prep = self.__class__.__new__(self.__class__)
prep.__dict__.update(self.__dict__)
prep.schema_for_object = schema._schema_getter(schema_translate_map)
return prep
def _escape_identifier(self, value):
"""Escape an identifier.
Subclasses should override this to provide database-dependent
escaping behavior.
"""
value = value.replace(self.escape_quote, self.escape_to_quote)
if self._double_percents:
value = value.replace("%", "%%")
return value
def _unescape_identifier(self, value):
"""Canonicalize an escaped identifier.
Subclasses should override this to provide database-dependent
unescaping behavior that reverses _escape_identifier.
"""
return value.replace(self.escape_to_quote, self.escape_quote)
def validate_sql_phrase(self, element, reg):
"""keyword sequence filter.
a filter for elements that are intended to represent keyword sequences,
such as "INITIALLY", "INITIALLY DEFERRED", etc. no special characters
should be present.
.. versionadded:: 1.3
"""
if element is not None and not reg.match(element):
raise exc.CompileError(
"Unexpected SQL phrase: %r (matching against %r)"
% (element, reg.pattern)
)
return element
def quote_identifier(self, value):
"""Quote an identifier.
Subclasses should override this to provide database-dependent
quoting behavior.
"""
return (
self.initial_quote
+ self._escape_identifier(value)
+ self.final_quote
)
def _requires_quotes(self, value):
"""Return True if the given identifier requires quoting."""
lc_value = value.lower()
return (
lc_value in self.reserved_words
or value[0] in self.illegal_initial_characters
or not self.legal_characters.match(util.text_type(value))
or (lc_value != value)
)
def _requires_quotes_illegal_chars(self, value):
"""Return True if the given identifier requires quoting, but
not taking case convention into account."""
return not self.legal_characters.match(util.text_type(value))
def quote_schema(self, schema, force=None):
"""Conditionally quote a schema name.
The name is quoted if it is a reserved word, contains quote-necessary
characters, or is an instance of :class:`.quoted_name` which includes
``quote`` set to ``True``.
Subclasses can override this to provide database-dependent
quoting behavior for schema names.
:param schema: string schema name
:param force: unused
.. deprecated:: 0.9
The :paramref:`.IdentifierPreparer.quote_schema.force`
parameter is deprecated and will be removed in a future
release. This flag has no effect on the behavior of the
:meth:`.IdentifierPreparer.quote` method; please refer to
:class:`.quoted_name`.
"""
if force is not None:
# not using the util.deprecated_params() decorator in this
# case because of the additional function call overhead on this
# very performance-critical spot.
util.warn_deprecated(
"The IdentifierPreparer.quote_schema.force parameter is "
"deprecated and will be removed in a future release. This "
"flag has no effect on the behavior of the "
"IdentifierPreparer.quote method; please refer to "
"quoted_name()."
)
return self.quote(schema)
def quote(self, ident, force=None):
"""Conditionally quote an identfier.
The identifier is quoted if it is a reserved word, contains
quote-necessary characters, or is an instance of
:class:`.quoted_name` which includes ``quote`` set to ``True``.
Subclasses can override this to provide database-dependent
quoting behavior for identifier names.
:param ident: string identifier
:param force: unused
.. deprecated:: 0.9
The :paramref:`.IdentifierPreparer.quote.force`
parameter is deprecated and will be removed in a future
release. This flag has no effect on the behavior of the
:meth:`.IdentifierPreparer.quote` method; please refer to
:class:`.quoted_name`.
"""
if force is not None:
# not using the util.deprecated_params() decorator in this
# case because of the additional function call overhead on this
# very performance-critical spot.
util.warn_deprecated(
"The IdentifierPreparer.quote.force parameter is "
"deprecated and will be removed in a future release. This "
"flag has no effect on the behavior of the "
"IdentifierPreparer.quote method; please refer to "
"quoted_name()."
)
force = getattr(ident, "quote", None)
if force is None:
if ident in self._strings:
return self._strings[ident]
else:
if self._requires_quotes(ident):
self._strings[ident] = self.quote_identifier(ident)
else:
self._strings[ident] = ident
return self._strings[ident]
elif force:
return self.quote_identifier(ident)
else:
return ident
def format_collation(self, collation_name):
if self.quote_case_sensitive_collations:
return self.quote(collation_name)
else:
return collation_name
def format_sequence(self, sequence, use_schema=True):
name = self.quote(sequence.name)
effective_schema = self.schema_for_object(sequence)
if (
not self.omit_schema
and use_schema
and effective_schema is not None
):
name = self.quote_schema(effective_schema) + "." + name
return name
def format_label(self, label, name=None):
return self.quote(name or label.name)
def format_alias(self, alias, name=None):
return self.quote(name or alias.name)
def format_savepoint(self, savepoint, name=None):
# Running the savepoint name through quoting is unnecessary
# for all known dialects. This is here to support potential
# third party use cases
ident = name or savepoint.ident
if self._requires_quotes(ident):
ident = self.quote_identifier(ident)
return ident
@util.dependencies("sqlalchemy.sql.naming")
def format_constraint(self, naming, constraint):
if constraint.name is elements._NONE_NAME:
name = naming._constraint_name_for_table(
constraint, constraint.table
)
if name is None:
return None
else:
name = constraint.name
if isinstance(name, elements._truncated_label):
# calculate these at format time so that ad-hoc changes
# to dialect.max_identifier_length etc. can be reflected
# as IdentifierPreparer is long lived
if constraint.__visit_name__ == "index":
max_ = (
self.dialect.max_index_name_length
or self.dialect.max_identifier_length
)
else:
max_ = (
self.dialect.max_constraint_name_length
or self.dialect.max_identifier_length
)
if len(name) > max_:
name = name[0 : max_ - 8] + "_" + util.md5_hex(name)[-4:]
else:
self.dialect.validate_identifier(name)
return self.quote(name)
def format_index(self, index):
return self.format_constraint(index)
def format_table(self, table, use_schema=True, name=None):
"""Prepare a quoted table and schema name."""
if name is None:
name = table.name
result = self.quote(name)
effective_schema = self.schema_for_object(table)
if not self.omit_schema and use_schema and effective_schema:
result = self.quote_schema(effective_schema) + "." + result
return result
def format_schema(self, name):
"""Prepare a quoted schema name."""
return self.quote(name)
def format_column(
self,
column,
use_table=False,
name=None,
table_name=None,
use_schema=False,
):
"""Prepare a quoted column name."""
if name is None:
name = column.name
if not getattr(column, "is_literal", False):
if use_table:
return (
self.format_table(
column.table, use_schema=use_schema, name=table_name
)
+ "."
+ self.quote(name)
)
else:
return self.quote(name)
else:
# literal textual elements get stuck into ColumnClause a lot,
# which shouldn't get quoted
if use_table:
return (
self.format_table(
column.table, use_schema=use_schema, name=table_name
)
+ "."
+ name
)
else:
return name
def format_table_seq(self, table, use_schema=True):
"""Format table name and schema as a tuple."""
# Dialects with more levels in their fully qualified references
# ('database', 'owner', etc.) could override this and return
# a longer sequence.
effective_schema = self.schema_for_object(table)
if not self.omit_schema and use_schema and effective_schema:
return (
self.quote_schema(effective_schema),
self.format_table(table, use_schema=False),
)
else:
return (self.format_table(table, use_schema=False),)
@util.memoized_property
def _r_identifiers(self):
initial, final, escaped_final = [
re.escape(s)
for s in (
self.initial_quote,
self.final_quote,
self._escape_identifier(self.final_quote),
)
]
r = re.compile(
r"(?:"
r"(?:%(initial)s((?:%(escaped)s|[^%(final)s])+)%(final)s"
r"|([^\.]+))(?=\.|$))+"
% {"initial": initial, "final": final, "escaped": escaped_final}
)
return r
def unformat_identifiers(self, identifiers):
"""Unpack 'schema.table.column'-like strings into components."""
r = self._r_identifiers
return [
self._unescape_identifier(i)
for i in [a or b for a, b in r.findall(identifiers)]
]
PK ! %# #
expression.pynu [ # sql/expression.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Defines the public namespace for SQL expression constructs.
Prior to version 0.9, this module contained all of "elements", "dml",
"default_comparator" and "selectable". The module was broken up
and most "factory" functions were moved to be grouped with their associated
class.
"""
__all__ = [
"Alias",
"any_",
"all_",
"ClauseElement",
"ColumnCollection",
"ColumnElement",
"CompoundSelect",
"Delete",
"FromClause",
"Insert",
"Join",
"Lateral",
"Select",
"Selectable",
"TableClause",
"Update",
"alias",
"and_",
"asc",
"between",
"bindparam",
"case",
"cast",
"column",
"cte",
"delete",
"desc",
"distinct",
"except_",
"except_all",
"exists",
"extract",
"func",
"modifier",
"collate",
"insert",
"intersect",
"intersect_all",
"join",
"label",
"lateral",
"literal",
"literal_column",
"not_",
"null",
"nullsfirst",
"nullslast",
"or_",
"outparam",
"outerjoin",
"over",
"select",
"subquery",
"table",
"text",
"tuple_",
"type_coerce",
"quoted_name",
"union",
"union_all",
"update",
"within_group",
"TableSample",
"tablesample",
]
from .base import _from_objects # noqa
from .base import ColumnCollection # noqa
from .base import Executable # noqa
from .base import Generative # noqa
from .base import PARSE_AUTOCOMMIT # noqa
from .dml import Delete # noqa
from .dml import Insert # noqa
from .dml import Update # noqa
from .dml import UpdateBase # noqa
from .dml import ValuesBase # noqa
from .elements import _clause_element_as_expr # noqa
from .elements import _clone # noqa
from .elements import _cloned_difference # noqa
from .elements import _cloned_intersection # noqa
from .elements import _column_as_key # noqa
from .elements import _corresponding_column_or_error # noqa
from .elements import _expression_literal_as_text # noqa
from .elements import _is_column # noqa
from .elements import _labeled # noqa
from .elements import _literal_as_binds # noqa
from .elements import _literal_as_column # noqa
from .elements import _literal_as_label_reference # noqa
from .elements import _literal_as_text # noqa
from .elements import _only_column_elements # noqa
from .elements import _select_iterables # noqa
from .elements import _string_or_unprintable # noqa
from .elements import _truncated_label # noqa
from .elements import between # noqa
from .elements import BinaryExpression # noqa
from .elements import BindParameter # noqa
from .elements import BooleanClauseList # noqa
from .elements import Case # noqa
from .elements import Cast # noqa
from .elements import ClauseElement # noqa
from .elements import ClauseList # noqa
from .elements import collate # noqa
from .elements import CollectionAggregate # noqa
from .elements import ColumnClause # noqa
from .elements import ColumnElement # noqa
from .elements import Extract # noqa
from .elements import False_ # noqa
from .elements import FunctionFilter # noqa
from .elements import Grouping # noqa
from .elements import Label # noqa
from .elements import literal # noqa
from .elements import literal_column # noqa
from .elements import not_ # noqa
from .elements import Null # noqa
from .elements import outparam # noqa
from .elements import Over # noqa
from .elements import quoted_name # noqa
from .elements import ReleaseSavepointClause # noqa
from .elements import RollbackToSavepointClause # noqa
from .elements import SavepointClause # noqa
from .elements import TextClause # noqa
from .elements import True_ # noqa
from .elements import Tuple # noqa
from .elements import TypeClause # noqa
from .elements import TypeCoerce # noqa
from .elements import UnaryExpression # noqa
from .elements import WithinGroup # noqa
from .functions import func # noqa
from .functions import Function # noqa
from .functions import FunctionElement # noqa
from .functions import modifier # noqa
from .selectable import _interpret_as_from # noqa
from .selectable import Alias # noqa
from .selectable import CompoundSelect # noqa
from .selectable import CTE # noqa
from .selectable import Exists # noqa
from .selectable import FromClause # noqa
from .selectable import FromGrouping # noqa
from .selectable import GenerativeSelect # noqa
from .selectable import HasCTE # noqa
from .selectable import HasPrefixes # noqa
from .selectable import HasSuffixes # noqa
from .selectable import Join # noqa
from .selectable import Lateral # noqa
from .selectable import ScalarSelect # noqa
from .selectable import Select # noqa
from .selectable import Selectable # noqa
from .selectable import SelectBase # noqa
from .selectable import subquery # noqa
from .selectable import TableClause # noqa
from .selectable import TableSample # noqa
from .selectable import TextAsFrom # noqa
from .visitors import Visitable # noqa
from ..util.langhelpers import public_factory # noqa
# factory functions - these pull class-bound constructors and classmethods
# from SQL elements and selectables into public functions. This allows
# the functions to be available in the sqlalchemy.sql.* namespace and
# to be auto-cross-documenting from the function to the class itself.
all_ = public_factory(CollectionAggregate._create_all, ".sql.expression.all_")
any_ = public_factory(CollectionAggregate._create_any, ".sql.expression.any_")
and_ = public_factory(BooleanClauseList.and_, ".sql.expression.and_")
alias = public_factory(Alias._factory, ".sql.expression.alias")
tablesample = public_factory(
TableSample._factory, ".sql.expression.tablesample"
)
lateral = public_factory(Lateral._factory, ".sql.expression.lateral")
or_ = public_factory(BooleanClauseList.or_, ".sql.expression.or_")
bindparam = public_factory(BindParameter, ".sql.expression.bindparam")
select = public_factory(Select, ".sql.expression.select")
text = public_factory(TextClause._create_text, ".sql.expression.text")
table = public_factory(TableClause, ".sql.expression.table")
column = public_factory(ColumnClause, ".sql.expression.column")
over = public_factory(Over, ".sql.expression.over")
within_group = public_factory(WithinGroup, ".sql.expression.within_group")
label = public_factory(Label, ".sql.expression.label")
case = public_factory(Case, ".sql.expression.case")
cast = public_factory(Cast, ".sql.expression.cast")
cte = public_factory(CTE._factory, ".sql.expression.cte")
extract = public_factory(Extract, ".sql.expression.extract")
tuple_ = public_factory(Tuple, ".sql.expression.tuple_")
except_ = public_factory(
CompoundSelect._create_except, ".sql.expression.except_"
)
except_all = public_factory(
CompoundSelect._create_except_all, ".sql.expression.except_all"
)
intersect = public_factory(
CompoundSelect._create_intersect, ".sql.expression.intersect"
)
intersect_all = public_factory(
CompoundSelect._create_intersect_all, ".sql.expression.intersect_all"
)
union = public_factory(CompoundSelect._create_union, ".sql.expression.union")
union_all = public_factory(
CompoundSelect._create_union_all, ".sql.expression.union_all"
)
exists = public_factory(Exists, ".sql.expression.exists")
nullsfirst = public_factory(
UnaryExpression._create_nullsfirst, ".sql.expression.nullsfirst"
)
nullslast = public_factory(
UnaryExpression._create_nullslast, ".sql.expression.nullslast"
)
asc = public_factory(UnaryExpression._create_asc, ".sql.expression.asc")
desc = public_factory(UnaryExpression._create_desc, ".sql.expression.desc")
distinct = public_factory(
UnaryExpression._create_distinct, ".sql.expression.distinct"
)
type_coerce = public_factory(TypeCoerce, ".sql.expression.type_coerce")
true = public_factory(True_._instance, ".sql.expression.true")
false = public_factory(False_._instance, ".sql.expression.false")
null = public_factory(Null._instance, ".sql.expression.null")
join = public_factory(Join._create_join, ".sql.expression.join")
outerjoin = public_factory(Join._create_outerjoin, ".sql.expression.outerjoin")
insert = public_factory(Insert, ".sql.expression.insert")
update = public_factory(Update, ".sql.expression.update")
delete = public_factory(Delete, ".sql.expression.delete")
funcfilter = public_factory(FunctionFilter, ".sql.expression.funcfilter")
# internal functions still being called from tests and the ORM,
# these might be better off in some other namespace
# old names for compatibility
_Executable = Executable
_BindParamClause = BindParameter
_Label = Label
_SelectBase = SelectBase
_BinaryExpression = BinaryExpression
_Cast = Cast
_Null = Null
_False = False_
_True = True_
_TextClause = TextClause
_UnaryExpression = UnaryExpression
_Case = Case
_Tuple = Tuple
_Over = Over
_Generative = Generative
_TypeClause = TypeClause
_Extract = Extract
_Exists = Exists
_Grouping = Grouping
_FromGrouping = FromGrouping
_ScalarSelect = ScalarSelect
PK ! D+T T schema.pynu [ # sql/schema.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""The schema module provides the building blocks for database metadata.
Each element within this module describes a database entity which can be
created and dropped, or is otherwise part of such an entity. Examples include
tables, columns, sequences, and indexes.
All entities are subclasses of :class:`~sqlalchemy.schema.SchemaItem`, and as
defined in this module they are intended to be agnostic of any vendor-specific
constructs.
A collection of entities are grouped into a unit called
:class:`~sqlalchemy.schema.MetaData`. MetaData serves as a logical grouping of
schema elements, and can also be associated with an actual database connection
such that operations involving the contained elements can contact the database
as needed.
Two of the elements here also build upon their "syntactic" counterparts, which
are defined in :class:`~sqlalchemy.sql.expression.`, specifically
:class:`~sqlalchemy.schema.Table` and :class:`~sqlalchemy.schema.Column`.
Since these objects are part of the SQL expression language, they are usable
as components in SQL expressions.
"""
from __future__ import absolute_import
import collections
import operator
import sqlalchemy
from . import ddl
from . import type_api
from . import visitors
from .base import _bind_or_error
from .base import ColumnCollection
from .base import DialectKWArgs
from .base import SchemaEventTarget
from .elements import _as_truncated
from .elements import _document_text_coercion
from .elements import _literal_as_text
from .elements import ClauseElement
from .elements import ColumnClause
from .elements import ColumnElement
from .elements import quoted_name
from .elements import TextClause
from .selectable import TableClause
from .. import event
from .. import exc
from .. import inspection
from .. import util
RETAIN_SCHEMA = util.symbol("retain_schema")
BLANK_SCHEMA = util.symbol(
"blank_schema",
"""Symbol indicating that a :class:`_schema.Table` or :class:`.Sequence`
should have 'None' for its schema, even if the parent
:class:`_schema.MetaData` has specified a schema.
.. versionadded:: 1.0.14
""",
)
def _get_table_key(name, schema):
if schema is None:
return name
else:
return schema + "." + name
# this should really be in sql/util.py but we'd have to
# break an import cycle
def _copy_expression(expression, source_table, target_table):
if source_table is None or target_table is None:
return expression
def replace(col):
if (
isinstance(col, Column)
and col.table is source_table
and col.key in source_table.c
):
return target_table.c[col.key]
else:
return None
return visitors.replacement_traverse(expression, {}, replace)
@inspection._self_inspects
class SchemaItem(SchemaEventTarget, visitors.Visitable):
"""Base class for items that define a database schema."""
__visit_name__ = "schema_item"
def _init_items(self, *args):
"""Initialize the list of child items for this SchemaItem."""
for item in args:
if item is not None:
try:
spwd = item._set_parent_with_dispatch
except AttributeError as err:
util.raise_(
exc.ArgumentError(
"'SchemaItem' object, such as a 'Column' or a "
"'Constraint' expected, got %r" % item
),
replace_context=err,
)
else:
spwd(self)
def get_children(self, **kwargs):
"""used to allow SchemaVisitor access"""
return []
def __repr__(self):
return util.generic_repr(self, omit_kwarg=["info"])
@property
@util.deprecated(
"0.9",
"The :attr:`.SchemaItem.quote` attribute is deprecated and will be "
"removed in a future release. Use the :attr:`.quoted_name.quote` "
"attribute on the ``name`` field of the target schema item to retrieve"
"quoted status.",
)
def quote(self):
"""Return the value of the ``quote`` flag passed
to this schema object, for those schema items which
have a ``name`` field.
"""
return self.name.quote
@util.memoized_property
def info(self):
"""Info dictionary associated with the object, allowing user-defined
data to be associated with this :class:`.SchemaItem`.
The dictionary is automatically generated when first accessed.
It can also be specified in the constructor of some objects,
such as :class:`_schema.Table` and :class:`_schema.Column`.
"""
return {}
def _schema_item_copy(self, schema_item):
if "info" in self.__dict__:
schema_item.info = self.info.copy()
schema_item.dispatch._update(self.dispatch)
return schema_item
def _translate_schema(self, effective_schema, map_):
return map_.get(effective_schema, effective_schema)
class Table(DialectKWArgs, SchemaItem, TableClause):
r"""Represent a table in a database.
e.g.::
mytable = Table("mytable", metadata,
Column('mytable_id', Integer, primary_key=True),
Column('value', String(50))
)
The :class:`_schema.Table`
object constructs a unique instance of itself based
on its name and optional schema name within the given
:class:`_schema.MetaData` object. Calling the :class:`_schema.Table`
constructor with the same name and same :class:`_schema.MetaData` argument
a second time will return the *same* :class:`_schema.Table`
object - in this way
the :class:`_schema.Table` constructor acts as a registry function.
.. seealso::
:ref:`metadata_describing` - Introduction to database metadata
Constructor arguments are as follows:
:param name: The name of this table as represented in the database.
The table name, along with the value of the ``schema`` parameter,
forms a key which uniquely identifies this :class:`_schema.Table`
within
the owning :class:`_schema.MetaData` collection.
Additional calls to :class:`_schema.Table` with the same name,
metadata,
and schema name will return the same :class:`_schema.Table` object.
Names which contain no upper case characters
will be treated as case insensitive names, and will not be quoted
unless they are a reserved word or contain special characters.
A name with any number of upper case characters is considered
to be case sensitive, and will be sent as quoted.
To enable unconditional quoting for the table name, specify the flag
``quote=True`` to the constructor, or use the :class:`.quoted_name`
construct to specify the name.
:param metadata: a :class:`_schema.MetaData`
object which will contain this
table. The metadata is used as a point of association of this table
with other tables which are referenced via foreign key. It also
may be used to associate this table with a particular
:class:`.Connectable`.
:param \*args: Additional positional arguments are used primarily
to add the list of :class:`_schema.Column`
objects contained within this
table. Similar to the style of a CREATE TABLE statement, other
:class:`.SchemaItem` constructs may be added here, including
:class:`.PrimaryKeyConstraint`, and
:class:`_schema.ForeignKeyConstraint`.
:param autoload: Defaults to False, unless
:paramref:`_schema.Table.autoload_with`
is set in which case it defaults to True; :class:`_schema.Column`
objects
for this table should be reflected from the database, possibly
augmenting or replacing existing :class:`_schema.Column`
objects that were
explicitly specified.
.. versionchanged:: 1.0.0 setting the
:paramref:`_schema.Table.autoload_with`
parameter implies that :paramref:`_schema.Table.autoload`
will default
to True.
.. seealso::
:ref:`metadata_reflection_toplevel`
:param autoload_replace: Defaults to ``True``; when using
:paramref:`_schema.Table.autoload`
in conjunction with :paramref:`_schema.Table.extend_existing`,
indicates
that :class:`_schema.Column` objects present in the already-existing
:class:`_schema.Table`
object should be replaced with columns of the same
name retrieved from the autoload process. When ``False``, columns
already present under existing names will be omitted from the
reflection process.
Note that this setting does not impact :class:`_schema.Column` objects
specified programmatically within the call to :class:`_schema.Table`
that
also is autoloading; those :class:`_schema.Column` objects will always
replace existing columns of the same name when
:paramref:`_schema.Table.extend_existing` is ``True``.
.. seealso::
:paramref:`_schema.Table.autoload`
:paramref:`_schema.Table.extend_existing`
:param autoload_with: An :class:`_engine.Engine` or
:class:`_engine.Connection` object
with which this :class:`_schema.Table` object will be reflected; when
set to a non-None value, it implies that
:paramref:`_schema.Table.autoload`
is ``True``. If left unset, but :paramref:`_schema.Table.autoload`
is
explicitly set to ``True``, an autoload operation will attempt to
proceed by locating an :class:`_engine.Engine` or
:class:`_engine.Connection` bound
to the underlying :class:`_schema.MetaData` object.
.. seealso::
:paramref:`_schema.Table.autoload`
:param extend_existing: When ``True``, indicates that if this
:class:`_schema.Table` is already present in the given
:class:`_schema.MetaData`,
apply further arguments within the constructor to the existing
:class:`_schema.Table`.
If :paramref:`_schema.Table.extend_existing` or
:paramref:`_schema.Table.keep_existing` are not set,
and the given name
of the new :class:`_schema.Table` refers to a :class:`_schema.Table`
that is
already present in the target :class:`_schema.MetaData` collection,
and
this :class:`_schema.Table`
specifies additional columns or other constructs
or flags that modify the table's state, an
error is raised. The purpose of these two mutually-exclusive flags
is to specify what action should be taken when a
:class:`_schema.Table`
is specified that matches an existing :class:`_schema.Table`,
yet specifies
additional constructs.
:paramref:`_schema.Table.extend_existing`
will also work in conjunction
with :paramref:`_schema.Table.autoload` to run a new reflection
operation against the database, even if a :class:`_schema.Table`
of the same name is already present in the target
:class:`_schema.MetaData`; newly reflected :class:`_schema.Column`
objects
and other options will be added into the state of the
:class:`_schema.Table`, potentially overwriting existing columns
and options of the same name.
As is always the case with :paramref:`_schema.Table.autoload`,
:class:`_schema.Column` objects can be specified in the same
:class:`_schema.Table`
constructor, which will take precedence. Below, the existing
table ``mytable`` will be augmented with :class:`_schema.Column`
objects
both reflected from the database, as well as the given
:class:`_schema.Column`
named "y"::
Table("mytable", metadata,
Column('y', Integer),
extend_existing=True,
autoload=True,
autoload_with=engine
)
.. seealso::
:paramref:`_schema.Table.autoload`
:paramref:`_schema.Table.autoload_replace`
:paramref:`_schema.Table.keep_existing`
:param implicit_returning: True by default - indicates that
RETURNING can be used by default to fetch newly inserted primary key
values, for backends which support this. Note that
:func:`_sa.create_engine` also provides an ``implicit_returning``
flag.
:param include_columns: A list of strings indicating a subset of
columns to be loaded via the ``autoload`` operation; table columns who
aren't present in this list will not be represented on the resulting
``Table`` object. Defaults to ``None`` which indicates all columns
should be reflected.
:param resolve_fks: Whether or not to reflect :class:`_schema.Table`
objects
related to this one via :class:`_schema.ForeignKey` objects, when
:paramref:`_schema.Table.autoload` or
:paramref:`_schema.Table.autoload_with` is
specified. Defaults to True. Set to False to disable reflection of
related tables as :class:`_schema.ForeignKey`
objects are encountered; may be
used either to save on SQL calls or to avoid issues with related tables
that can't be accessed. Note that if a related table is already present
in the :class:`_schema.MetaData` collection, or becomes present later,
a
:class:`_schema.ForeignKey` object associated with this
:class:`_schema.Table` will
resolve to that table normally.
.. versionadded:: 1.3
.. seealso::
:paramref:`.MetaData.reflect.resolve_fks`
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
:param keep_existing: When ``True``, indicates that if this Table
is already present in the given :class:`_schema.MetaData`, ignore
further arguments within the constructor to the existing
:class:`_schema.Table`, and return the :class:`_schema.Table`
object as
originally created. This is to allow a function that wishes
to define a new :class:`_schema.Table` on first call, but on
subsequent calls will return the same :class:`_schema.Table`,
without any of the declarations (particularly constraints)
being applied a second time.
If :paramref:`_schema.Table.extend_existing` or
:paramref:`_schema.Table.keep_existing` are not set,
and the given name
of the new :class:`_schema.Table` refers to a :class:`_schema.Table`
that is
already present in the target :class:`_schema.MetaData` collection,
and
this :class:`_schema.Table`
specifies additional columns or other constructs
or flags that modify the table's state, an
error is raised. The purpose of these two mutually-exclusive flags
is to specify what action should be taken when a
:class:`_schema.Table`
is specified that matches an existing :class:`_schema.Table`,
yet specifies
additional constructs.
.. seealso::
:paramref:`_schema.Table.extend_existing`
:param listeners: A list of tuples of the form ``(, )``
which will be passed to :func:`.event.listen` upon construction.
This alternate hook to :func:`.event.listen` allows the establishment
of a listener function specific to this :class:`_schema.Table` before
the "autoload" process begins. Particularly useful for
the :meth:`.DDLEvents.column_reflect` event::
def listen_for_reflect(table, column_info):
"handle the column reflection event"
# ...
t = Table(
'sometable',
autoload=True,
listeners=[
('column_reflect', listen_for_reflect)
])
:param mustexist: When ``True``, indicates that this Table must already
be present in the given :class:`_schema.MetaData` collection, else
an exception is raised.
:param prefixes:
A list of strings to insert after CREATE in the CREATE TABLE
statement. They will be separated by spaces.
:param quote: Force quoting of this table's name on or off, corresponding
to ``True`` or ``False``. When left at its default of ``None``,
the column identifier will be quoted according to whether the name is
case sensitive (identifiers with at least one upper case character are
treated as case sensitive), or if it's a reserved word. This flag
is only needed to force quoting of a reserved word which is not known
by the SQLAlchemy dialect.
:param quote_schema: same as 'quote' but applies to the schema identifier.
:param schema: The schema name for this table, which is required if
the table resides in a schema other than the default selected schema
for the engine's database connection. Defaults to ``None``.
If the owning :class:`_schema.MetaData` of this :class:`_schema.Table`
specifies its
own :paramref:`_schema.MetaData.schema` parameter,
then that schema name will
be applied to this :class:`_schema.Table`
if the schema parameter here is set
to ``None``. To set a blank schema name on a :class:`_schema.Table`
that
would otherwise use the schema set on the owning
:class:`_schema.MetaData`,
specify the special symbol :attr:`.BLANK_SCHEMA`.
.. versionadded:: 1.0.14 Added the :attr:`.BLANK_SCHEMA` symbol to
allow a :class:`_schema.Table`
to have a blank schema name even when the
parent :class:`_schema.MetaData` specifies
:paramref:`_schema.MetaData.schema`.
The quoting rules for the schema name are the same as those for the
``name`` parameter, in that quoting is applied for reserved words or
case-sensitive names; to enable unconditional quoting for the schema
name, specify the flag ``quote_schema=True`` to the constructor, or use
the :class:`.quoted_name` construct to specify the name.
:param useexisting: the same as :paramref:`_schema.Table.extend_existing`.
:param comment: Optional string that will render an SQL comment on table
creation.
.. versionadded:: 1.2 Added the :paramref:`_schema.Table.comment`
parameter
to :class:`_schema.Table`.
:param \**kw: Additional keyword arguments not mentioned above are
dialect specific, and passed in the form ``_``.
See the documentation regarding an individual dialect at
:ref:`dialect_toplevel` for detail on documented arguments.
"""
__visit_name__ = "table"
@util.deprecated_params(
useexisting=(
"0.7",
"The :paramref:`_schema.Table.useexisting` "
"parameter is deprecated and "
"will be removed in a future release. Please use "
":paramref:`_schema.Table.extend_existing`.",
)
)
def __new__(cls, *args, **kw):
if not args:
# python3k pickle seems to call this
return object.__new__(cls)
try:
name, metadata, args = args[0], args[1], args[2:]
except IndexError:
raise TypeError("Table() takes at least two arguments")
schema = kw.get("schema", None)
if schema is None:
schema = metadata.schema
elif schema is BLANK_SCHEMA:
schema = None
keep_existing = kw.pop("keep_existing", False)
extend_existing = kw.pop("extend_existing", False)
if "useexisting" in kw:
if extend_existing:
msg = "useexisting is synonymous with extend_existing."
raise exc.ArgumentError(msg)
extend_existing = kw.pop("useexisting", False)
if keep_existing and extend_existing:
msg = "keep_existing and extend_existing are mutually exclusive."
raise exc.ArgumentError(msg)
mustexist = kw.pop("mustexist", False)
key = _get_table_key(name, schema)
if key in metadata.tables:
if not keep_existing and not extend_existing and bool(args):
raise exc.InvalidRequestError(
"Table '%s' is already defined for this MetaData "
"instance. Specify 'extend_existing=True' "
"to redefine "
"options and columns on an "
"existing Table object." % key
)
table = metadata.tables[key]
if extend_existing:
table._init_existing(*args, **kw)
return table
else:
if mustexist:
raise exc.InvalidRequestError("Table '%s' not defined" % (key))
table = object.__new__(cls)
table.dispatch.before_parent_attach(table, metadata)
metadata._add_table(name, schema, table)
try:
table._init(name, metadata, *args, **kw)
table.dispatch.after_parent_attach(table, metadata)
return table
except:
with util.safe_reraise():
metadata._remove_table(name, schema)
@property
@util.deprecated(
"0.9",
"The :meth:`.SchemaItem.quote` method is deprecated and will be "
"removed in a future release. Use the :attr:`.quoted_name.quote` "
"attribute on the ``schema`` field of the target schema item to "
"retrieve quoted status.",
)
def quote_schema(self):
"""Return the value of the ``quote_schema`` flag passed
to this :class:`_schema.Table`.
"""
return self.schema.quote
def __init__(self, *args, **kw):
"""Constructor for :class:`_schema.Table`.
This method is a no-op. See the top-level
documentation for :class:`_schema.Table`
for constructor arguments.
"""
# __init__ is overridden to prevent __new__ from
# calling the superclass constructor.
def _init(self, name, metadata, *args, **kwargs):
super(Table, self).__init__(
quoted_name(name, kwargs.pop("quote", None))
)
self.metadata = metadata
self.schema = kwargs.pop("schema", None)
if self.schema is None:
self.schema = metadata.schema
elif self.schema is BLANK_SCHEMA:
self.schema = None
else:
quote_schema = kwargs.pop("quote_schema", None)
self.schema = quoted_name(self.schema, quote_schema)
self.indexes = set()
self.constraints = set()
self._columns = ColumnCollection()
PrimaryKeyConstraint(
_implicit_generated=True
)._set_parent_with_dispatch(self)
self.foreign_keys = set()
self._extra_dependencies = set()
if self.schema is not None:
self.fullname = "%s.%s" % (self.schema, self.name)
else:
self.fullname = self.name
autoload_with = kwargs.pop("autoload_with", None)
autoload = kwargs.pop("autoload", autoload_with is not None)
# this argument is only used with _init_existing()
kwargs.pop("autoload_replace", True)
_extend_on = kwargs.pop("_extend_on", None)
resolve_fks = kwargs.pop("resolve_fks", True)
include_columns = kwargs.pop("include_columns", None)
self.implicit_returning = kwargs.pop("implicit_returning", True)
self.comment = kwargs.pop("comment", None)
if "info" in kwargs:
self.info = kwargs.pop("info")
if "listeners" in kwargs:
listeners = kwargs.pop("listeners")
for evt, fn in listeners:
event.listen(self, evt, fn)
self._prefixes = kwargs.pop("prefixes", [])
self._extra_kwargs(**kwargs)
# load column definitions from the database if 'autoload' is defined
# we do it after the table is in the singleton dictionary to support
# circular foreign keys
if autoload:
self._autoload(
metadata,
autoload_with,
include_columns,
_extend_on=_extend_on,
resolve_fks=resolve_fks,
)
# initialize all the column, etc. objects. done after reflection to
# allow user-overrides
self._init_items(*args)
def _autoload(
self,
metadata,
autoload_with,
include_columns,
exclude_columns=(),
resolve_fks=True,
_extend_on=None,
):
if autoload_with:
autoload_with.run_callable(
autoload_with.dialect.reflecttable,
self,
include_columns,
exclude_columns,
resolve_fks,
_extend_on=_extend_on,
)
else:
bind = _bind_or_error(
metadata,
msg="No engine is bound to this Table's MetaData. "
"Pass an engine to the Table via "
"autoload_with=, "
"or associate the MetaData with an engine via "
"metadata.bind=",
)
bind.run_callable(
bind.dialect.reflecttable,
self,
include_columns,
exclude_columns,
resolve_fks,
_extend_on=_extend_on,
)
@property
def _sorted_constraints(self):
"""Return the set of constraints as a list, sorted by creation
order.
"""
return sorted(self.constraints, key=lambda c: c._creation_order)
@property
def foreign_key_constraints(self):
""":class:`_schema.ForeignKeyConstraint` objects referred to by this
:class:`_schema.Table`.
This list is produced from the collection of
:class:`_schema.ForeignKey`
objects currently associated.
.. versionadded:: 1.0.0
"""
return set(fkc.constraint for fkc in self.foreign_keys)
def _init_existing(self, *args, **kwargs):
autoload_with = kwargs.pop("autoload_with", None)
autoload = kwargs.pop("autoload", autoload_with is not None)
autoload_replace = kwargs.pop("autoload_replace", True)
schema = kwargs.pop("schema", None)
_extend_on = kwargs.pop("_extend_on", None)
if schema and schema != self.schema:
raise exc.ArgumentError(
"Can't change schema of existing table from '%s' to '%s'",
(self.schema, schema),
)
include_columns = kwargs.pop("include_columns", None)
resolve_fks = kwargs.pop("resolve_fks", True)
if include_columns is not None:
for c in self.c:
if c.name not in include_columns:
self._columns.remove(c)
for key in ("quote", "quote_schema"):
if key in kwargs:
raise exc.ArgumentError(
"Can't redefine 'quote' or 'quote_schema' arguments"
)
if "comment" in kwargs:
self.comment = kwargs.pop("comment", None)
if "info" in kwargs:
self.info = kwargs.pop("info")
if autoload:
if not autoload_replace:
# don't replace columns already present.
# we'd like to do this for constraints also however we don't
# have simple de-duping for unnamed constraints.
exclude_columns = [c.name for c in self.c]
else:
exclude_columns = ()
self._autoload(
self.metadata,
autoload_with,
include_columns,
exclude_columns,
resolve_fks,
_extend_on=_extend_on,
)
self._extra_kwargs(**kwargs)
self._init_items(*args)
def _extra_kwargs(self, **kwargs):
self._validate_dialect_kwargs(kwargs)
def _init_collections(self):
pass
def _reset_exported(self):
pass
@property
def _autoincrement_column(self):
return self.primary_key._autoincrement_column
@property
def key(self):
"""Return the 'key' for this :class:`_schema.Table`.
This value is used as the dictionary key within the
:attr:`_schema.MetaData.tables` collection. It is typically the same
as that of :attr:`_schema.Table.name` for a table with no
:attr:`_schema.Table.schema`
set; otherwise it is typically of the form
``schemaname.tablename``.
"""
return _get_table_key(self.name, self.schema)
def __repr__(self):
return "Table(%s)" % ", ".join(
[repr(self.name)]
+ [repr(self.metadata)]
+ [repr(x) for x in self.columns]
+ ["%s=%s" % (k, repr(getattr(self, k))) for k in ["schema"]]
)
def __str__(self):
return _get_table_key(self.description, self.schema)
@property
def bind(self):
"""Return the connectable associated with this Table."""
return self.metadata and self.metadata.bind or None
def add_is_dependent_on(self, table):
"""Add a 'dependency' for this Table.
This is another Table object which must be created
first before this one can, or dropped after this one.
Usually, dependencies between tables are determined via
ForeignKey objects. However, for other situations that
create dependencies outside of foreign keys (rules, inheriting),
this method can manually establish such a link.
"""
self._extra_dependencies.add(table)
def append_column(self, column):
"""Append a :class:`_schema.Column` to this :class:`_schema.Table`.
The "key" of the newly added :class:`_schema.Column`, i.e. the
value of its ``.key`` attribute, will then be available
in the ``.c`` collection of this :class:`_schema.Table`, and the
column definition will be included in any CREATE TABLE, SELECT,
UPDATE, etc. statements generated from this :class:`_schema.Table`
construct.
Note that this does **not** change the definition of the table
as it exists within any underlying database, assuming that
table has already been created in the database. Relational
databases support the addition of columns to existing tables
using the SQL ALTER command, which would need to be
emitted for an already-existing table that doesn't contain
the newly added column.
"""
column._set_parent_with_dispatch(self)
def append_constraint(self, constraint):
"""Append a :class:`_schema.Constraint` to this
:class:`_schema.Table`.
This has the effect of the constraint being included in any
future CREATE TABLE statement, assuming specific DDL creation
events have not been associated with the given
:class:`_schema.Constraint` object.
Note that this does **not** produce the constraint within the
relational database automatically, for a table that already exists
in the database. To add a constraint to an
existing relational database table, the SQL ALTER command must
be used. SQLAlchemy also provides the
:class:`.AddConstraint` construct which can produce this SQL when
invoked as an executable clause.
"""
constraint._set_parent_with_dispatch(self)
@util.deprecated(
"0.7",
"the :meth:`_schema.Table.append_ddl_listener` "
"method is deprecated and "
"will be removed in a future release. Please refer to "
":class:`.DDLEvents`.",
)
def append_ddl_listener(self, event_name, listener):
"""Append a DDL event listener to this ``Table``."""
def adapt_listener(target, connection, **kw):
listener(event_name, target, connection)
event.listen(self, "" + event_name.replace("-", "_"), adapt_listener)
def _set_parent(self, metadata):
metadata._add_table(self.name, self.schema, self)
self.metadata = metadata
def get_children(
self, column_collections=True, schema_visitor=False, **kw
):
if not schema_visitor:
return TableClause.get_children(
self, column_collections=column_collections, **kw
)
else:
if column_collections:
return list(self.columns)
else:
return []
def exists(self, bind=None):
"""Return True if this table exists."""
if bind is None:
bind = _bind_or_error(self)
return bind.run_callable(
bind.dialect.has_table, self.name, schema=self.schema
)
def create(self, bind=None, checkfirst=False):
"""Issue a ``CREATE`` statement for this
:class:`_schema.Table`, using the given :class:`.Connectable`
for connectivity.
.. seealso::
:meth:`_schema.MetaData.create_all`.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
def drop(self, bind=None, checkfirst=False):
"""Issue a ``DROP`` statement for this
:class:`_schema.Table`, using the given :class:`.Connectable`
for connectivity.
.. seealso::
:meth:`_schema.MetaData.drop_all`.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaDropper, self, checkfirst=checkfirst)
def tometadata(
self,
metadata,
schema=RETAIN_SCHEMA,
referred_schema_fn=None,
name=None,
):
"""Return a copy of this :class:`_schema.Table`
associated with a different
:class:`_schema.MetaData`.
E.g.::
m1 = MetaData()
user = Table('user', m1, Column('id', Integer, primary_key=True))
m2 = MetaData()
user_copy = user.tometadata(m2)
:param metadata: Target :class:`_schema.MetaData` object,
into which the
new :class:`_schema.Table` object will be created.
:param schema: optional string name indicating the target schema.
Defaults to the special symbol :attr:`.RETAIN_SCHEMA` which indicates
that no change to the schema name should be made in the new
:class:`_schema.Table`. If set to a string name, the new
:class:`_schema.Table`
will have this new name as the ``.schema``. If set to ``None``, the
schema will be set to that of the schema set on the target
:class:`_schema.MetaData`, which is typically ``None`` as well,
unless
set explicitly::
m2 = MetaData(schema='newschema')
# user_copy_one will have "newschema" as the schema name
user_copy_one = user.tometadata(m2, schema=None)
m3 = MetaData() # schema defaults to None
# user_copy_two will have None as the schema name
user_copy_two = user.tometadata(m3, schema=None)
:param referred_schema_fn: optional callable which can be supplied
in order to provide for the schema name that should be assigned
to the referenced table of a :class:`_schema.ForeignKeyConstraint`.
The callable accepts this parent :class:`_schema.Table`, the
target schema that we are changing to, the
:class:`_schema.ForeignKeyConstraint` object, and the existing
"target schema" of that constraint. The function should return the
string schema name that should be applied.
E.g.::
def referred_schema_fn(table, to_schema,
constraint, referred_schema):
if referred_schema == 'base_tables':
return referred_schema
else:
return to_schema
new_table = table.tometadata(m2, schema="alt_schema",
referred_schema_fn=referred_schema_fn)
.. versionadded:: 0.9.2
:param name: optional string name indicating the target table name.
If not specified or None, the table name is retained. This allows
a :class:`_schema.Table` to be copied to the same
:class:`_schema.MetaData` target
with a new name.
.. versionadded:: 1.0.0
"""
if name is None:
name = self.name
if schema is RETAIN_SCHEMA:
schema = self.schema
elif schema is None:
schema = metadata.schema
key = _get_table_key(name, schema)
if key in metadata.tables:
util.warn(
"Table '%s' already exists within the given "
"MetaData - not copying." % self.description
)
return metadata.tables[key]
args = []
for c in self.columns:
args.append(c.copy(schema=schema))
table = Table(
name,
metadata,
schema=schema,
comment=self.comment,
*args,
**self.kwargs
)
for c in self.constraints:
if isinstance(c, ForeignKeyConstraint):
referred_schema = c._referred_schema
if referred_schema_fn:
fk_constraint_schema = referred_schema_fn(
self, schema, c, referred_schema
)
else:
fk_constraint_schema = (
schema if referred_schema == self.schema else None
)
table.append_constraint(
c.copy(schema=fk_constraint_schema, target_table=table)
)
elif not c._type_bound:
# skip unique constraints that would be generated
# by the 'unique' flag on Column
if c._column_flag:
continue
table.append_constraint(
c.copy(schema=schema, target_table=table)
)
for index in self.indexes:
# skip indexes that would be generated
# by the 'index' flag on Column
if index._column_flag:
continue
Index(
index.name,
unique=index.unique,
*[
_copy_expression(expr, self, table)
for expr in index.expressions
],
_table=table,
**index.kwargs
)
return self._schema_item_copy(table)
class Column(DialectKWArgs, SchemaItem, ColumnClause):
"""Represents a column in a database table."""
__visit_name__ = "column"
def __init__(self, *args, **kwargs):
r"""
Construct a new ``Column`` object.
:param name: The name of this column as represented in the database.
This argument may be the first positional argument, or specified
via keyword.
Names which contain no upper case characters
will be treated as case insensitive names, and will not be quoted
unless they are a reserved word. Names with any number of upper
case characters will be quoted and sent exactly. Note that this
behavior applies even for databases which standardize upper
case names as case insensitive such as Oracle.
The name field may be omitted at construction time and applied
later, at any time before the Column is associated with a
:class:`_schema.Table`. This is to support convenient
usage within the :mod:`~sqlalchemy.ext.declarative` extension.
:param type\_: The column's type, indicated using an instance which
subclasses :class:`~sqlalchemy.types.TypeEngine`. If no arguments
are required for the type, the class of the type can be sent
as well, e.g.::
# use a type with arguments
Column('data', String(50))
# use no arguments
Column('level', Integer)
The ``type`` argument may be the second positional argument
or specified by keyword.
If the ``type`` is ``None`` or is omitted, it will first default to
the special type :class:`.NullType`. If and when this
:class:`_schema.Column` is made to refer to another column using
:class:`_schema.ForeignKey` and/or
:class:`_schema.ForeignKeyConstraint`, the type
of the remote-referenced column will be copied to this column as
well, at the moment that the foreign key is resolved against that
remote :class:`_schema.Column` object.
.. versionchanged:: 0.9.0
Support for propagation of type to a :class:`_schema.Column`
from its
:class:`_schema.ForeignKey` object has been improved and should be
more reliable and timely.
:param \*args: Additional positional arguments include various
:class:`.SchemaItem` derived constructs which will be applied
as options to the column. These include instances of
:class:`.Constraint`, :class:`_schema.ForeignKey`,
:class:`.ColumnDefault`,
:class:`.Sequence`, :class:`.Computed`. In some cases an
equivalent keyword argument is available such as ``server_default``,
``default`` and ``unique``.
:param autoincrement: Set up "auto increment" semantics for an integer
primary key column. The default value is the string ``"auto"``
which indicates that a single-column primary key that is of
an INTEGER type with no stated client-side or python-side defaults
should receive auto increment semantics automatically;
all other varieties of primary key columns will not. This
includes that :term:`DDL` such as PostgreSQL SERIAL or MySQL
AUTO_INCREMENT will be emitted for this column during a table
create, as well as that the column is assumed to generate new
integer primary key values when an INSERT statement invokes which
will be retrieved by the dialect.
The flag may be set to ``True`` to indicate that a column which
is part of a composite (e.g. multi-column) primary key should
have autoincrement semantics, though note that only one column
within a primary key may have this setting. It can also
be set to ``True`` to indicate autoincrement semantics on a
column that has a client-side or server-side default configured,
however note that not all dialects can accommodate all styles
of default as an "autoincrement". It can also be
set to ``False`` on a single-column primary key that has a
datatype of INTEGER in order to disable auto increment semantics
for that column.
.. versionchanged:: 1.1 The autoincrement flag now defaults to
``"auto"`` which indicates autoincrement semantics by default
for single-column integer primary keys only; for composite
(multi-column) primary keys, autoincrement is never implicitly
enabled; as always, ``autoincrement=True`` will allow for
at most one of those columns to be an "autoincrement" column.
``autoincrement=True`` may also be set on a
:class:`_schema.Column`
that has an explicit client-side or server-side default,
subject to limitations of the backend database and dialect.
The setting *only* has an effect for columns which are:
* Integer derived (i.e. INT, SMALLINT, BIGINT).
* Part of the primary key
* Not referring to another column via :class:`_schema.ForeignKey`,
unless
the value is specified as ``'ignore_fk'``::
# turn on autoincrement for this column despite
# the ForeignKey()
Column('id', ForeignKey('other.id'),
primary_key=True, autoincrement='ignore_fk')
It is typically not desirable to have "autoincrement" enabled on a
column that refers to another via foreign key, as such a column is
required to refer to a value that originates from elsewhere.
The setting has these two effects on columns that meet the
above criteria:
* DDL issued for the column will include database-specific
keywords intended to signify this column as an
"autoincrement" column, such as AUTO INCREMENT on MySQL,
SERIAL on PostgreSQL, and IDENTITY on MS-SQL. It does
*not* issue AUTOINCREMENT for SQLite since this is a
special SQLite flag that is not required for autoincrementing
behavior.
.. seealso::
:ref:`sqlite_autoincrement`
* The column will be considered to be available using an
"autoincrement" method specific to the backend database, such
as calling upon ``cursor.lastrowid``, using RETURNING in an
INSERT statement to get at a sequence-generated value, or using
special functions such as "SELECT scope_identity()".
These methods are highly specific to the DBAPIs and databases in
use and vary greatly, so care should be taken when associating
``autoincrement=True`` with a custom default generation function.
:param default: A scalar, Python callable, or
:class:`_expression.ColumnElement` expression representing the
*default value* for this column, which will be invoked upon insert
if this column is otherwise not specified in the VALUES clause of
the insert. This is a shortcut to using :class:`.ColumnDefault` as
a positional argument; see that class for full detail on the
structure of the argument.
Contrast this argument to
:paramref:`_schema.Column.server_default`
which creates a default generator on the database side.
.. seealso::
:ref:`metadata_defaults_toplevel`
:param doc: optional String that can be used by the ORM or similar
to document attributes on the Python side. This attribute does
**not** render SQL comments; use the
:paramref:`_schema.Column.comment`
parameter for this purpose.
:param key: An optional string identifier which will identify this
``Column`` object on the :class:`_schema.Table`.
When a key is provided,
this is the only identifier referencing the ``Column`` within the
application, including ORM attribute mapping; the ``name`` field
is used only when rendering SQL.
:param index: When ``True``, indicates that a :class:`_schema.Index`
construct will be automatically generated for this
:class:`_schema.Column`, which will result in a "CREATE INDEX"
statement being emitted for the :class:`_schema.Table` when the DDL
create operation is invoked.
Using this flag is equivalent to making use of the
:class:`_schema.Index` construct explicitly at the level of the
:class:`_schema.Table` construct itself::
Table(
"some_table",
metadata,
Column("x", Integer),
Index("ix_some_table_x", "x")
)
To add the :paramref:`_schema.Index.unique` flag to the
:class:`_schema.Index`, set both the
:paramref:`_schema.Column.unique` and
:paramref:`_schema.Column.index` flags to True simultaneously,
which will have the effect of rendering the "CREATE UNIQUE INDEX"
DDL instruction instead of "CREATE INDEX".
The name of the index is generated using the
:ref:`default naming convention `
which for the :class:`_schema.Index` construct is of the form
``ix__``.
As this flag is intended only as a convenience for the common case
of adding a single-column, default configured index to a table
definition, explicit use of the :class:`_schema.Index` construct
should be preferred for most use cases, including composite indexes
that encompass more than one column, indexes with SQL expressions
or ordering, backend-specific index configuration options, and
indexes that use a specific name.
.. note:: the :attr:`_schema.Column.index` attribute on
:class:`_schema.Column`
**does not indicate** if this column is indexed or not, only
if this flag was explicitly set here. To view indexes on
a column, view the :attr:`_schema.Table.indexes` collection
or use :meth:`_reflection.Inspector.get_indexes`.
.. seealso::
:ref:`schema_indexes`
:ref:`constraint_naming_conventions`
:paramref:`_schema.Column.unique`
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
:param nullable: When set to ``False``, will cause the "NOT NULL"
phrase to be added when generating DDL for the column. When
``True``, will normally generate nothing (in SQL this defaults to
"NULL"), except in some very specific backend-specific edge cases
where "NULL" may render explicitly. Defaults to ``True`` unless
:paramref:`_schema.Column.primary_key` is also ``True``,
in which case it
defaults to ``False``. This parameter is only used when issuing
CREATE TABLE statements.
:param onupdate: A scalar, Python callable, or
:class:`~sqlalchemy.sql.expression.ClauseElement` representing a
default value to be applied to the column within UPDATE
statements, which will be invoked upon update if this column is not
present in the SET clause of the update. This is a shortcut to
using :class:`.ColumnDefault` as a positional argument with
``for_update=True``.
.. seealso::
:ref:`metadata_defaults` - complete discussion of onupdate
:param primary_key: If ``True``, marks this column as a primary key
column. Multiple columns can have this flag set to specify
composite primary keys. As an alternative, the primary key of a
:class:`_schema.Table` can be specified via an explicit
:class:`.PrimaryKeyConstraint` object.
:param server_default: A :class:`.FetchedValue` instance, str, Unicode
or :func:`~sqlalchemy.sql.expression.text` construct representing
the DDL DEFAULT value for the column.
String types will be emitted as-is, surrounded by single quotes::
Column('x', Text, server_default="val")
x TEXT DEFAULT 'val'
A :func:`~sqlalchemy.sql.expression.text` expression will be
rendered as-is, without quotes::
Column('y', DateTime, server_default=text('NOW()'))
y DATETIME DEFAULT NOW()
Strings and text() will be converted into a
:class:`.DefaultClause` object upon initialization.
Use :class:`.FetchedValue` to indicate that an already-existing
column will generate a default value on the database side which
will be available to SQLAlchemy for post-fetch after inserts. This
construct does not specify any DDL and the implementation is left
to the database, such as via a trigger.
.. seealso::
:ref:`server_defaults` - complete discussion of server side
defaults
:param server_onupdate: A :class:`.FetchedValue` instance
representing a database-side default generation function,
such as a trigger. This
indicates to SQLAlchemy that a newly generated value will be
available after updates. This construct does not actually
implement any kind of generation function within the database,
which instead must be specified separately.
.. warning:: This directive **does not** currently produce MySQL's
"ON UPDATE CURRENT_TIMESTAMP()" clause. See
:ref:`mysql_timestamp_onupdate` for background on how to
produce this clause.
.. seealso::
:ref:`triggered_columns`
:param quote: Force quoting of this column's name on or off,
corresponding to ``True`` or ``False``. When left at its default
of ``None``, the column identifier will be quoted according to
whether the name is case sensitive (identifiers with at least one
upper case character are treated as case sensitive), or if it's a
reserved word. This flag is only needed to force quoting of a
reserved word which is not known by the SQLAlchemy dialect.
:param unique: When ``True``, and the :paramref:`_schema.Column.index`
parameter is left at its default value of ``False``,
indicates that a :class:`_schema.UniqueConstraint`
construct will be automatically generated for this
:class:`_schema.Column`,
which will result in a "UNIQUE CONSTRAINT" clause referring
to this column being included
in the ``CREATE TABLE`` statement emitted, when the DDL create
operation for the :class:`_schema.Table` object is invoked.
When this flag is ``True`` while the
:paramref:`_schema.Column.index` parameter is simultaneously
set to ``True``, the effect instead is that a
:class:`_schema.Index` construct which includes the
:paramref:`_schema.Index.unique` parameter set to ``True``
is generated. See the documentation for
:paramref:`_schema.Column.index` for additional detail.
Using this flag is equivalent to making use of the
:class:`_schema.UniqueConstraint` construct explicitly at the
level of the :class:`_schema.Table` construct itself::
Table(
"some_table",
metadata,
Column("x", Integer),
UniqueConstraint("x")
)
The :paramref:`_schema.UniqueConstraint.name` parameter
of the unique constraint object is left at its default value
of ``None``; in the absence of a :ref:`naming convention `
for the enclosing :class:`_schema.MetaData`, the UNIQUE CONSTRAINT
construct will be emitted as unnamed, which typically invokes
a database-specific naming convention to take place.
As this flag is intended only as a convenience for the common case
of adding a single-column, default configured unique constraint to a table
definition, explicit use of the :class:`_schema.UniqueConstraint` construct
should be preferred for most use cases, including composite constraints
that encompass more than one column, backend-specific index configuration options, and
constraints that use a specific name.
.. note:: the :attr:`_schema.Column.unique` attribute on
:class:`_schema.Column`
**does not indicate** if this column has a unique constraint or
not, only if this flag was explicitly set here. To view
indexes and unique constraints that may involve this column,
view the
:attr:`_schema.Table.indexes` and/or
:attr:`_schema.Table.constraints` collections or use
:meth:`_reflection.Inspector.get_indexes` and/or
:meth:`_reflection.Inspector.get_unique_constraints`
.. seealso::
:ref:`schema_unique_constraint`
:ref:`constraint_naming_conventions`
:paramref:`_schema.Column.index`
:param system: When ``True``, indicates this is a "system" column,
that is a column which is automatically made available by the
database, and should not be included in the columns list for a
``CREATE TABLE`` statement.
For more elaborate scenarios where columns should be
conditionally rendered differently on different backends,
consider custom compilation rules for :class:`.CreateColumn`.
:param comment: Optional string that will render an SQL comment on
table creation.
.. versionadded:: 1.2 Added the
:paramref:`_schema.Column.comment`
parameter to :class:`_schema.Column`.
""" # noqa E501
name = kwargs.pop("name", None)
type_ = kwargs.pop("type_", None)
args = list(args)
if args:
if isinstance(args[0], util.string_types):
if name is not None:
raise exc.ArgumentError(
"May not pass name positionally and as a keyword."
)
name = args.pop(0)
if args:
coltype = args[0]
if hasattr(coltype, "_sqla_type"):
if type_ is not None:
raise exc.ArgumentError(
"May not pass type_ positionally and as a keyword."
)
type_ = args.pop(0)
if name is not None:
name = quoted_name(name, kwargs.pop("quote", None))
elif "quote" in kwargs:
raise exc.ArgumentError(
"Explicit 'name' is required when " "sending 'quote' argument"
)
super(Column, self).__init__(name, type_)
self.key = kwargs.pop("key", name)
self.primary_key = kwargs.pop("primary_key", False)
self.nullable = kwargs.pop("nullable", not self.primary_key)
self.default = kwargs.pop("default", None)
self.server_default = kwargs.pop("server_default", None)
self.server_onupdate = kwargs.pop("server_onupdate", None)
# these default to None because .index and .unique is *not*
# an informational flag about Column - there can still be an
# Index or UniqueConstraint referring to this Column.
self.index = kwargs.pop("index", None)
self.unique = kwargs.pop("unique", None)
self.system = kwargs.pop("system", False)
self.doc = kwargs.pop("doc", None)
self.onupdate = kwargs.pop("onupdate", None)
self.autoincrement = kwargs.pop("autoincrement", "auto")
self.constraints = set()
self.foreign_keys = set()
self.comment = kwargs.pop("comment", None)
self.computed = None
# check if this Column is proxying another column
if "_proxies" in kwargs:
self._proxies = kwargs.pop("_proxies")
# otherwise, add DDL-related events
elif isinstance(self.type, SchemaEventTarget):
self.type._set_parent_with_dispatch(self)
if self.default is not None:
if isinstance(self.default, (ColumnDefault, Sequence)):
args.append(self.default)
else:
if getattr(self.type, "_warn_on_bytestring", False):
if isinstance(self.default, util.binary_type):
util.warn(
"Unicode column '%s' has non-unicode "
"default value %r specified."
% (self.key, self.default)
)
args.append(ColumnDefault(self.default))
if self.server_default is not None:
if isinstance(self.server_default, FetchedValue):
args.append(self.server_default._as_for_update(False))
else:
args.append(DefaultClause(self.server_default))
if self.onupdate is not None:
if isinstance(self.onupdate, (ColumnDefault, Sequence)):
args.append(self.onupdate)
else:
args.append(ColumnDefault(self.onupdate, for_update=True))
if self.server_onupdate is not None:
if isinstance(self.server_onupdate, FetchedValue):
args.append(self.server_onupdate._as_for_update(True))
else:
args.append(
DefaultClause(self.server_onupdate, for_update=True)
)
self._init_items(*args)
util.set_creation_order(self)
if "info" in kwargs:
self.info = kwargs.pop("info")
self._extra_kwargs(**kwargs)
def _extra_kwargs(self, **kwargs):
self._validate_dialect_kwargs(kwargs)
# @property
# def quote(self):
# return getattr(self.name, "quote", None)
def __str__(self):
if self.name is None:
return "(no name)"
elif self.table is not None:
if self.table.named_with_column:
return self.table.description + "." + self.description
else:
return self.description
else:
return self.description
def references(self, column):
"""Return True if this Column references the given column via foreign
key."""
for fk in self.foreign_keys:
if fk.column.proxy_set.intersection(column.proxy_set):
return True
else:
return False
def append_foreign_key(self, fk):
fk._set_parent_with_dispatch(self)
def __repr__(self):
kwarg = []
if self.key != self.name:
kwarg.append("key")
if self.primary_key:
kwarg.append("primary_key")
if not self.nullable:
kwarg.append("nullable")
if self.onupdate:
kwarg.append("onupdate")
if self.default:
kwarg.append("default")
if self.server_default:
kwarg.append("server_default")
if self.comment:
kwarg.append("comment")
return "Column(%s)" % ", ".join(
[repr(self.name)]
+ [repr(self.type)]
+ [repr(x) for x in self.foreign_keys if x is not None]
+ [repr(x) for x in self.constraints]
+ [
(
self.table is not None
and "table=<%s>" % self.table.description
or "table=None"
)
]
+ ["%s=%s" % (k, repr(getattr(self, k))) for k in kwarg]
)
def _set_parent(self, table):
if not self.name:
raise exc.ArgumentError(
"Column must be constructed with a non-blank name or "
"assign a non-blank .name before adding to a Table."
)
if self.key is None:
self.key = self.name
existing = getattr(self, "table", None)
if existing is not None and existing is not table:
raise exc.ArgumentError(
"Column object '%s' already assigned to Table '%s'"
% (self.key, existing.description)
)
if self.key in table._columns:
col = table._columns.get(self.key)
if col is not self:
for fk in col.foreign_keys:
table.foreign_keys.remove(fk)
if fk.constraint in table.constraints:
# this might have been removed
# already, if it's a composite constraint
# and more than one col being replaced
table.constraints.remove(fk.constraint)
table._columns.replace(self)
self.table = table
if self.primary_key:
table.primary_key._replace(self)
elif self.key in table.primary_key:
raise exc.ArgumentError(
"Trying to redefine primary-key column '%s' as a "
"non-primary-key column on table '%s'"
% (self.key, table.fullname)
)
if self.index:
if isinstance(self.index, util.string_types):
raise exc.ArgumentError(
"The 'index' keyword argument on Column is boolean only. "
"To create indexes with a specific name, create an "
"explicit Index object external to the Table."
)
table.append_constraint(
Index(
None, self.key, unique=bool(self.unique), _column_flag=True
)
)
elif self.unique:
if isinstance(self.unique, util.string_types):
raise exc.ArgumentError(
"The 'unique' keyword argument on Column is boolean "
"only. To create unique constraints or indexes with a "
"specific name, append an explicit UniqueConstraint to "
"the Table's list of elements, or create an explicit "
"Index object external to the Table."
)
table.append_constraint(
UniqueConstraint(self.key, _column_flag=True)
)
self._setup_on_memoized_fks(lambda fk: fk._set_remote_table(table))
def _setup_on_memoized_fks(self, fn):
fk_keys = [
((self.table.key, self.key), False),
((self.table.key, self.name), True),
]
for fk_key, link_to_name in fk_keys:
if fk_key in self.table.metadata._fk_memos:
for fk in self.table.metadata._fk_memos[fk_key]:
if fk.link_to_name is link_to_name:
fn(fk)
def _on_table_attach(self, fn):
if self.table is not None:
fn(self, self.table)
else:
event.listen(self, "after_parent_attach", fn)
def copy(self, **kw):
"""Create a copy of this ``Column``, uninitialized.
This is used in :meth:`_schema.Table.tometadata`.
"""
# Constraint objects plus non-constraint-bound ForeignKey objects
args = [
c.copy(**kw) for c in self.constraints if not c._type_bound
] + [c.copy(**kw) for c in self.foreign_keys if not c.constraint]
# ticket #5276
column_kwargs = {}
for dialect_name in self.dialect_options:
dialect_options = self.dialect_options[dialect_name]._non_defaults
for (
dialect_option_key,
dialect_option_value,
) in dialect_options.items():
column_kwargs[
dialect_name + "_" + dialect_option_key
] = dialect_option_value
server_default = self.server_default
server_onupdate = self.server_onupdate
if isinstance(server_default, Computed):
server_default = server_onupdate = None
args.append(self.server_default.copy(**kw))
type_ = self.type
if isinstance(type_, SchemaEventTarget):
type_ = type_.copy(**kw)
c = self._constructor(
name=self.name,
type_=type_,
key=self.key,
primary_key=self.primary_key,
nullable=self.nullable,
unique=self.unique,
system=self.system,
# quote=self.quote, # disabled 2013-08-27 (commit 031ef080)
index=self.index,
autoincrement=self.autoincrement,
default=self.default,
server_default=server_default,
onupdate=self.onupdate,
server_onupdate=server_onupdate,
doc=self.doc,
comment=self.comment,
*args,
**column_kwargs
)
return self._schema_item_copy(c)
def _make_proxy(
self, selectable, name=None, key=None, name_is_truncatable=False, **kw
):
"""Create a *proxy* for this column.
This is a copy of this ``Column`` referenced by a different parent
(such as an alias or select statement). The column should
be used only in select scenarios, as its full DDL/default
information is not transferred.
"""
fk = [
ForeignKey(f.column, _constraint=f.constraint)
for f in self.foreign_keys
]
if name is None and self.name is None:
raise exc.InvalidRequestError(
"Cannot initialize a sub-selectable"
" with this Column object until its 'name' has "
"been assigned."
)
try:
c = self._constructor(
_as_truncated(name or self.name)
if name_is_truncatable
else (name or self.name),
self.type,
key=key if key else name if name else self.key,
primary_key=self.primary_key,
nullable=self.nullable,
_proxies=[self],
*fk
)
except TypeError as err:
util.raise_(
TypeError(
"Could not create a copy of this %r object. "
"Ensure the class includes a _constructor() "
"attribute or method which accepts the "
"standard Column constructor arguments, or "
"references the Column class itself." % self.__class__
),
from_=err,
)
c.table = selectable
selectable._columns.add(c)
if selectable._is_clone_of is not None:
c._is_clone_of = selectable._is_clone_of.columns.get(c.key)
if self.primary_key:
selectable.primary_key.add(c)
c.dispatch.after_parent_attach(c, selectable)
return c
def get_children(self, schema_visitor=False, **kwargs):
if schema_visitor:
return (
[x for x in (self.default, self.onupdate) if x is not None]
+ list(self.foreign_keys)
+ list(self.constraints)
)
else:
return ColumnClause.get_children(self, **kwargs)
class ForeignKey(DialectKWArgs, SchemaItem):
"""Defines a dependency between two columns.
``ForeignKey`` is specified as an argument to a :class:`_schema.Column`
object,
e.g.::
t = Table("remote_table", metadata,
Column("remote_id", ForeignKey("main_table.id"))
)
Note that ``ForeignKey`` is only a marker object that defines
a dependency between two columns. The actual constraint
is in all cases represented by the :class:`_schema.ForeignKeyConstraint`
object. This object will be generated automatically when
a ``ForeignKey`` is associated with a :class:`_schema.Column` which
in turn is associated with a :class:`_schema.Table`. Conversely,
when :class:`_schema.ForeignKeyConstraint` is applied to a
:class:`_schema.Table`,
``ForeignKey`` markers are automatically generated to be
present on each associated :class:`_schema.Column`, which are also
associated with the constraint object.
Note that you cannot define a "composite" foreign key constraint,
that is a constraint between a grouping of multiple parent/child
columns, using ``ForeignKey`` objects. To define this grouping,
the :class:`_schema.ForeignKeyConstraint` object must be used, and applied
to the :class:`_schema.Table`. The associated ``ForeignKey`` objects
are created automatically.
The ``ForeignKey`` objects associated with an individual
:class:`_schema.Column`
object are available in the `foreign_keys` collection
of that column.
Further examples of foreign key configuration are in
:ref:`metadata_foreignkeys`.
"""
__visit_name__ = "foreign_key"
def __init__(
self,
column,
_constraint=None,
use_alter=False,
name=None,
onupdate=None,
ondelete=None,
deferrable=None,
initially=None,
link_to_name=False,
match=None,
info=None,
**dialect_kw
):
r"""
Construct a column-level FOREIGN KEY.
The :class:`_schema.ForeignKey` object when constructed generates a
:class:`_schema.ForeignKeyConstraint`
which is associated with the parent
:class:`_schema.Table` object's collection of constraints.
:param column: A single target column for the key relationship. A
:class:`_schema.Column` object or a column name as a string:
``tablename.columnkey`` or ``schema.tablename.columnkey``.
``columnkey`` is the ``key`` which has been assigned to the column
(defaults to the column name itself), unless ``link_to_name`` is
``True`` in which case the rendered name of the column is used.
:param name: Optional string. An in-database name for the key if
`constraint` is not provided.
:param onupdate: Optional string. If set, emit ON UPDATE when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param ondelete: Optional string. If set, emit ON DELETE when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param deferrable: Optional bool. If set, emit DEFERRABLE or NOT
DEFERRABLE when issuing DDL for this constraint.
:param initially: Optional string. If set, emit INITIALLY when
issuing DDL for this constraint.
:param link_to_name: if True, the string name given in ``column`` is
the rendered name of the referenced column, not its locally
assigned ``key``.
:param use_alter: passed to the underlying
:class:`_schema.ForeignKeyConstraint`
to indicate the constraint should
be generated/dropped externally from the CREATE TABLE/ DROP TABLE
statement. See :paramref:`_schema.ForeignKeyConstraint.use_alter`
for further description.
.. seealso::
:paramref:`_schema.ForeignKeyConstraint.use_alter`
:ref:`use_alter`
:param match: Optional string. If set, emit MATCH when issuing
DDL for this constraint. Typical values include SIMPLE, PARTIAL
and FULL.
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
:param \**dialect_kw: Additional keyword arguments are dialect
specific, and passed in the form ``_``. The
arguments are ultimately handled by a corresponding
:class:`_schema.ForeignKeyConstraint`.
See the documentation regarding
an individual dialect at :ref:`dialect_toplevel` for detail on
documented arguments.
.. versionadded:: 0.9.2
"""
self._colspec = column
if isinstance(self._colspec, util.string_types):
self._table_column = None
else:
if hasattr(self._colspec, "__clause_element__"):
self._table_column = self._colspec.__clause_element__()
else:
self._table_column = self._colspec
if not isinstance(self._table_column, ColumnClause):
raise exc.ArgumentError(
"String, Column, or Column-bound argument "
"expected, got %r" % self._table_column
)
elif not isinstance(
self._table_column.table, (util.NoneType, TableClause)
):
raise exc.ArgumentError(
"ForeignKey received Column not bound "
"to a Table, got: %r" % self._table_column.table
)
# the linked ForeignKeyConstraint.
# ForeignKey will create this when parent Column
# is attached to a Table, *or* ForeignKeyConstraint
# object passes itself in when creating ForeignKey
# markers.
self.constraint = _constraint
self.parent = None
self.use_alter = use_alter
self.name = name
self.onupdate = onupdate
self.ondelete = ondelete
self.deferrable = deferrable
self.initially = initially
self.link_to_name = link_to_name
self.match = match
if info:
self.info = info
self._unvalidated_dialect_kw = dialect_kw
def __repr__(self):
return "ForeignKey(%r)" % self._get_colspec()
def copy(self, schema=None):
"""Produce a copy of this :class:`_schema.ForeignKey` object.
The new :class:`_schema.ForeignKey` will not be bound
to any :class:`_schema.Column`.
This method is usually used by the internal
copy procedures of :class:`_schema.Column`, :class:`_schema.Table`,
and :class:`_schema.MetaData`.
:param schema: The returned :class:`_schema.ForeignKey` will
reference the original table and column name, qualified
by the given string schema name.
"""
fk = ForeignKey(
self._get_colspec(schema=schema),
use_alter=self.use_alter,
name=self.name,
onupdate=self.onupdate,
ondelete=self.ondelete,
deferrable=self.deferrable,
initially=self.initially,
link_to_name=self.link_to_name,
match=self.match,
**self._unvalidated_dialect_kw
)
return self._schema_item_copy(fk)
def _get_colspec(self, schema=None, table_name=None):
"""Return a string based 'column specification' for this
:class:`_schema.ForeignKey`.
This is usually the equivalent of the string-based "tablename.colname"
argument first passed to the object's constructor.
"""
if schema:
_schema, tname, colname = self._column_tokens
if table_name is not None:
tname = table_name
return "%s.%s.%s" % (schema, tname, colname)
elif table_name:
schema, tname, colname = self._column_tokens
if schema:
return "%s.%s.%s" % (schema, table_name, colname)
else:
return "%s.%s" % (table_name, colname)
elif self._table_column is not None:
return "%s.%s" % (
self._table_column.table.fullname,
self._table_column.key,
)
else:
return self._colspec
@property
def _referred_schema(self):
return self._column_tokens[0]
def _table_key(self):
if self._table_column is not None:
if self._table_column.table is None:
return None
else:
return self._table_column.table.key
else:
schema, tname, colname = self._column_tokens
return _get_table_key(tname, schema)
target_fullname = property(_get_colspec)
def references(self, table):
"""Return True if the given :class:`_schema.Table`
is referenced by this
:class:`_schema.ForeignKey`."""
return table.corresponding_column(self.column) is not None
def get_referent(self, table):
"""Return the :class:`_schema.Column` in the given
:class:`_schema.Table`
referenced by this :class:`_schema.ForeignKey`.
Returns None if this :class:`_schema.ForeignKey`
does not reference the given
:class:`_schema.Table`.
"""
return table.corresponding_column(self.column)
@util.memoized_property
def _column_tokens(self):
"""parse a string-based _colspec into its component parts."""
m = self._get_colspec().split(".")
if m is None:
raise exc.ArgumentError(
"Invalid foreign key column specification: %s" % self._colspec
)
if len(m) == 1:
tname = m.pop()
colname = None
else:
colname = m.pop()
tname = m.pop()
# A FK between column 'bar' and table 'foo' can be
# specified as 'foo', 'foo.bar', 'dbo.foo.bar',
# 'otherdb.dbo.foo.bar'. Once we have the column name and
# the table name, treat everything else as the schema
# name. Some databases (e.g. Sybase) support
# inter-database foreign keys. See tickets#1341 and --
# indirectly related -- Ticket #594. This assumes that '.'
# will never appear *within* any component of the FK.
if len(m) > 0:
schema = ".".join(m)
else:
schema = None
return schema, tname, colname
def _resolve_col_tokens(self):
if self.parent is None:
raise exc.InvalidRequestError(
"this ForeignKey object does not yet have a "
"parent Column associated with it."
)
elif self.parent.table is None:
raise exc.InvalidRequestError(
"this ForeignKey's parent column is not yet associated "
"with a Table."
)
parenttable = self.parent.table
# assertion
# basically Column._make_proxy() sends the actual
# target Column to the ForeignKey object, so the
# string resolution here is never called.
for c in self.parent.base_columns:
if isinstance(c, Column):
assert c.table is parenttable
break
else:
assert False
######################
schema, tname, colname = self._column_tokens
if schema is None and parenttable.metadata.schema is not None:
schema = parenttable.metadata.schema
tablekey = _get_table_key(tname, schema)
return parenttable, tablekey, colname
def _link_to_col_by_colstring(self, parenttable, table, colname):
if not hasattr(self.constraint, "_referred_table"):
self.constraint._referred_table = table
else:
assert self.constraint._referred_table is table
_column = None
if colname is None:
# colname is None in the case that ForeignKey argument
# was specified as table name only, in which case we
# match the column name to the same column on the
# parent.
key = self.parent
_column = table.c.get(self.parent.key, None)
elif self.link_to_name:
key = colname
for c in table.c:
if c.name == colname:
_column = c
else:
key = colname
_column = table.c.get(colname, None)
if _column is None:
raise exc.NoReferencedColumnError(
"Could not initialize target column "
"for ForeignKey '%s' on table '%s': "
"table '%s' has no column named '%s'"
% (self._colspec, parenttable.name, table.name, key),
table.name,
key,
)
self._set_target_column(_column)
def _set_target_column(self, column):
# propagate TypeEngine to parent if it didn't have one
if self.parent.type._isnull:
self.parent.type = column.type
# super-edgy case, if other FKs point to our column,
# they'd get the type propagated out also.
if isinstance(self.parent.table, Table):
def set_type(fk):
if fk.parent.type._isnull:
fk.parent.type = column.type
self.parent._setup_on_memoized_fks(set_type)
self.column = column
@util.memoized_property
def column(self):
"""Return the target :class:`_schema.Column` referenced by this
:class:`_schema.ForeignKey`.
If no target column has been established, an exception
is raised.
.. versionchanged:: 0.9.0
Foreign key target column resolution now occurs as soon as both
the ForeignKey object and the remote Column to which it refers
are both associated with the same MetaData object.
"""
if isinstance(self._colspec, util.string_types):
parenttable, tablekey, colname = self._resolve_col_tokens()
if tablekey not in parenttable.metadata:
raise exc.NoReferencedTableError(
"Foreign key associated with column '%s' could not find "
"table '%s' with which to generate a "
"foreign key to target column '%s'"
% (self.parent, tablekey, colname),
tablekey,
)
elif parenttable.key not in parenttable.metadata:
raise exc.InvalidRequestError(
"Table %s is no longer associated with its "
"parent MetaData" % parenttable
)
else:
raise exc.NoReferencedColumnError(
"Could not initialize target column for "
"ForeignKey '%s' on table '%s': "
"table '%s' has no column named '%s'"
% (self._colspec, parenttable.name, tablekey, colname),
tablekey,
colname,
)
elif hasattr(self._colspec, "__clause_element__"):
_column = self._colspec.__clause_element__()
return _column
else:
_column = self._colspec
return _column
def _set_parent(self, column):
if self.parent is not None and self.parent is not column:
raise exc.InvalidRequestError(
"This ForeignKey already has a parent !"
)
self.parent = column
self.parent.foreign_keys.add(self)
self.parent._on_table_attach(self._set_table)
def _set_remote_table(self, table):
parenttable, tablekey, colname = self._resolve_col_tokens()
self._link_to_col_by_colstring(parenttable, table, colname)
self.constraint._validate_dest_table(table)
def _remove_from_metadata(self, metadata):
parenttable, table_key, colname = self._resolve_col_tokens()
fk_key = (table_key, colname)
if self in metadata._fk_memos[fk_key]:
# TODO: no test coverage for self not in memos
metadata._fk_memos[fk_key].remove(self)
def _set_table(self, column, table):
# standalone ForeignKey - create ForeignKeyConstraint
# on the hosting Table when attached to the Table.
if self.constraint is None and isinstance(table, Table):
self.constraint = ForeignKeyConstraint(
[],
[],
use_alter=self.use_alter,
name=self.name,
onupdate=self.onupdate,
ondelete=self.ondelete,
deferrable=self.deferrable,
initially=self.initially,
match=self.match,
**self._unvalidated_dialect_kw
)
self.constraint._append_element(column, self)
self.constraint._set_parent_with_dispatch(table)
table.foreign_keys.add(self)
# set up remote ".column" attribute, or a note to pick it
# up when the other Table/Column shows up
if isinstance(self._colspec, util.string_types):
parenttable, table_key, colname = self._resolve_col_tokens()
fk_key = (table_key, colname)
if table_key in parenttable.metadata.tables:
table = parenttable.metadata.tables[table_key]
try:
self._link_to_col_by_colstring(parenttable, table, colname)
except exc.NoReferencedColumnError:
# this is OK, we'll try later
pass
parenttable.metadata._fk_memos[fk_key].append(self)
elif hasattr(self._colspec, "__clause_element__"):
_column = self._colspec.__clause_element__()
self._set_target_column(_column)
else:
_column = self._colspec
self._set_target_column(_column)
class _NotAColumnExpr(object):
def _not_a_column_expr(self):
raise exc.InvalidRequestError(
"This %s cannot be used directly "
"as a column expression." % self.__class__.__name__
)
__clause_element__ = self_group = lambda self: self._not_a_column_expr()
_from_objects = property(lambda self: self._not_a_column_expr())
class DefaultGenerator(_NotAColumnExpr, SchemaItem):
"""Base class for column *default* values."""
__visit_name__ = "default_generator"
is_sequence = False
is_server_default = False
column = None
def __init__(self, for_update=False):
self.for_update = for_update
def _set_parent(self, column):
self.column = column
if self.for_update:
self.column.onupdate = self
else:
self.column.default = self
def execute(self, bind=None, **kwargs):
if bind is None:
bind = _bind_or_error(self)
return bind.execute(self, **kwargs)
def _execute_on_connection(self, connection, multiparams, params):
return connection._execute_default(self, multiparams, params)
@property
def bind(self):
"""Return the connectable associated with this default."""
if getattr(self, "column", None) is not None:
return self.column.table.bind
else:
return None
class ColumnDefault(DefaultGenerator):
"""A plain default value on a column.
This could correspond to a constant, a callable function,
or a SQL clause.
:class:`.ColumnDefault` is generated automatically
whenever the ``default``, ``onupdate`` arguments of
:class:`_schema.Column` are used. A :class:`.ColumnDefault`
can be passed positionally as well.
For example, the following::
Column('foo', Integer, default=50)
Is equivalent to::
Column('foo', Integer, ColumnDefault(50))
"""
def __init__(self, arg, **kwargs):
"""Construct a new :class:`.ColumnDefault`.
:param arg: argument representing the default value.
May be one of the following:
* a plain non-callable Python value, such as a
string, integer, boolean, or other simple type.
The default value will be used as is each time.
* a SQL expression, that is one which derives from
:class:`_expression.ColumnElement`. The SQL expression will
be rendered into the INSERT or UPDATE statement,
or in the case of a primary key column when
RETURNING is not used may be
pre-executed before an INSERT within a SELECT.
* A Python callable. The function will be invoked for each
new row subject to an INSERT or UPDATE.
The callable must accept exactly
zero or one positional arguments. The one-argument form
will receive an instance of the :class:`.ExecutionContext`,
which provides contextual information as to the current
:class:`_engine.Connection` in use as well as the current
statement and parameters.
"""
super(ColumnDefault, self).__init__(**kwargs)
if isinstance(arg, FetchedValue):
raise exc.ArgumentError(
"ColumnDefault may not be a server-side default type."
)
if util.callable(arg):
arg = self._maybe_wrap_callable(arg)
self.arg = arg
@util.memoized_property
def is_callable(self):
return util.callable(self.arg)
@util.memoized_property
def is_clause_element(self):
return isinstance(self.arg, ClauseElement)
@util.memoized_property
def is_scalar(self):
return (
not self.is_callable
and not self.is_clause_element
and not self.is_sequence
)
@util.memoized_property
@util.dependencies("sqlalchemy.sql.sqltypes")
def _arg_is_typed(self, sqltypes):
if self.is_clause_element:
return not isinstance(self.arg.type, sqltypes.NullType)
else:
return False
def _maybe_wrap_callable(self, fn):
"""Wrap callables that don't accept a context.
This is to allow easy compatibility with default callables
that aren't specific to accepting of a context.
"""
try:
argspec = util.get_callable_argspec(fn, no_self=True)
except TypeError:
return util.wrap_callable(lambda ctx: fn(), fn)
defaulted = argspec[3] is not None and len(argspec[3]) or 0
positionals = len(argspec[0]) - defaulted
if positionals == 0:
return util.wrap_callable(lambda ctx: fn(), fn)
elif positionals == 1:
return fn
else:
raise exc.ArgumentError(
"ColumnDefault Python function takes zero or one "
"positional arguments"
)
def _visit_name(self):
if self.for_update:
return "column_onupdate"
else:
return "column_default"
__visit_name__ = property(_visit_name)
def __repr__(self):
return "ColumnDefault(%r)" % (self.arg,)
class IdentityOptions(object):
"""Defines options for a named database sequence or an identity column.
.. versionadded:: 1.3.18
.. seealso::
:class:`.Sequence`
"""
def __init__(
self,
start=None,
increment=None,
minvalue=None,
maxvalue=None,
nominvalue=None,
nomaxvalue=None,
cycle=None,
cache=None,
order=None,
):
"""Construct a :class:`.IdentityOptions` object.
See the :class:`.Sequence` documentation for a complete description
of the parameters
:param start: the starting index of the sequence.
:param increment: the increment value of the sequence.
:param minvalue: the minimum value of the sequence.
:param maxvalue: the maximum value of the sequence.
:param nominvalue: no minimum value of the sequence.
:param nomaxvalue: no maximum value of the sequence.
:param cycle: allows the sequence to wrap around when the maxvalue
or minvalue has been reached.
:param cache: optional integer value; number of future values in the
sequence which are calculated in advance.
:param order: optional boolean value; if ``True``, renders the
ORDER keyword.
name.
"""
self.start = start
self.increment = increment
self.minvalue = minvalue
self.maxvalue = maxvalue
self.nominvalue = nominvalue
self.nomaxvalue = nomaxvalue
self.cycle = cycle
self.cache = cache
self.order = order
class Sequence(IdentityOptions, DefaultGenerator):
"""Represents a named database sequence.
The :class:`.Sequence` object represents the name and configurational
parameters of a database sequence. It also represents
a construct that can be "executed" by a SQLAlchemy :class:`_engine.Engine`
or :class:`_engine.Connection`,
rendering the appropriate "next value" function
for the target database and returning a result.
The :class:`.Sequence` is typically associated with a primary key column::
some_table = Table(
'some_table', metadata,
Column('id', Integer, Sequence('some_table_seq'),
primary_key=True)
)
When CREATE TABLE is emitted for the above :class:`_schema.Table`, if the
target platform supports sequences, a CREATE SEQUENCE statement will
be emitted as well. For platforms that don't support sequences,
the :class:`.Sequence` construct is ignored.
.. seealso::
:class:`.CreateSequence`
:class:`.DropSequence`
"""
__visit_name__ = "sequence"
is_sequence = True
def __init__(
self,
name,
start=None,
increment=None,
minvalue=None,
maxvalue=None,
nominvalue=None,
nomaxvalue=None,
cycle=None,
schema=None,
cache=None,
order=None,
optional=False,
quote=None,
metadata=None,
quote_schema=None,
for_update=False,
):
"""Construct a :class:`.Sequence` object.
:param name: the name of the sequence.
:param start: the starting index of the sequence. This value is
used when the CREATE SEQUENCE command is emitted to the database
as the value of the "START WITH" clause. If ``None``, the
clause is omitted, which on most platforms indicates a starting
value of 1.
:param increment: the increment value of the sequence. This
value is used when the CREATE SEQUENCE command is emitted to
the database as the value of the "INCREMENT BY" clause. If ``None``,
the clause is omitted, which on most platforms indicates an
increment of 1.
:param minvalue: the minimum value of the sequence. This
value is used when the CREATE SEQUENCE command is emitted to
the database as the value of the "MINVALUE" clause. If ``None``,
the clause is omitted, which on most platforms indicates a
minvalue of 1 and -2^63-1 for ascending and descending sequences,
respectively.
.. versionadded:: 1.0.7
:param maxvalue: the maximum value of the sequence. This
value is used when the CREATE SEQUENCE command is emitted to
the database as the value of the "MAXVALUE" clause. If ``None``,
the clause is omitted, which on most platforms indicates a
maxvalue of 2^63-1 and -1 for ascending and descending sequences,
respectively.
.. versionadded:: 1.0.7
:param nominvalue: no minimum value of the sequence. This
value is used when the CREATE SEQUENCE command is emitted to
the database as the value of the "NO MINVALUE" clause. If ``None``,
the clause is omitted, which on most platforms indicates a
minvalue of 1 and -2^63-1 for ascending and descending sequences,
respectively.
.. versionadded:: 1.0.7
:param nomaxvalue: no maximum value of the sequence. This
value is used when the CREATE SEQUENCE command is emitted to
the database as the value of the "NO MAXVALUE" clause. If ``None``,
the clause is omitted, which on most platforms indicates a
maxvalue of 2^63-1 and -1 for ascending and descending sequences,
respectively.
.. versionadded:: 1.0.7
:param cycle: allows the sequence to wrap around when the maxvalue
or minvalue has been reached by an ascending or descending sequence
respectively. This value is used when the CREATE SEQUENCE command
is emitted to the database as the "CYCLE" clause. If the limit is
reached, the next number generated will be the minvalue or maxvalue,
respectively. If cycle=False (the default) any calls to nextval
after the sequence has reached its maximum value will return an
error.
.. versionadded:: 1.0.7
:param schema: optional schema name for the sequence, if located
in a schema other than the default. The rules for selecting the
schema name when a :class:`_schema.MetaData`
is also present are the same
as that of :paramref:`_schema.Table.schema`.
:param cache: optional integer value; number of future values in the
sequence which are calculated in advance. Renders the CACHE keyword
understood by Oracle and PostgreSQL.
.. versionadded:: 1.1.12
:param order: optional boolean value; if ``True``, renders the
ORDER keyword, understood by Oracle, indicating the sequence is
definitively ordered. May be necessary to provide deterministic
ordering using Oracle RAC.
.. versionadded:: 1.1.12
:param optional: boolean value, when ``True``, indicates that this
:class:`.Sequence` object only needs to be explicitly generated
on backends that don't provide another way to generate primary
key identifiers. Currently, it essentially means, "don't create
this sequence on the PostgreSQL backend, where the SERIAL keyword
creates a sequence for us automatically".
:param quote: boolean value, when ``True`` or ``False``, explicitly
forces quoting of the :paramref:`_schema.Sequence.name` on or off.
When left at its default of ``None``, normal quoting rules based
on casing and reserved words take place.
:param quote_schema: Set the quoting preferences for the ``schema``
name.
:param metadata: optional :class:`_schema.MetaData` object which this
:class:`.Sequence` will be associated with. A :class:`.Sequence`
that is associated with a :class:`_schema.MetaData`
gains the following
capabilities:
* The :class:`.Sequence` will inherit the
:paramref:`_schema.MetaData.schema`
parameter specified to the target :class:`_schema.MetaData`, which
affects the production of CREATE / DROP DDL, if any.
* The :meth:`.Sequence.create` and :meth:`.Sequence.drop` methods
automatically use the engine bound to the :class:`_schema.MetaData`
object, if any.
* The :meth:`_schema.MetaData.create_all` and
:meth:`_schema.MetaData.drop_all`
methods will emit CREATE / DROP for this :class:`.Sequence`,
even if the :class:`.Sequence` is not associated with any
:class:`_schema.Table` / :class:`_schema.Column`
that's a member of this
:class:`_schema.MetaData`.
The above behaviors can only occur if the :class:`.Sequence` is
explicitly associated with the :class:`_schema.MetaData`
via this parameter.
.. seealso::
:ref:`sequence_metadata` - full discussion of the
:paramref:`.Sequence.metadata` parameter.
:param for_update: Indicates this :class:`.Sequence`, when associated
with a :class:`_schema.Column`,
should be invoked for UPDATE statements
on that column's table, rather than for INSERT statements, when
no value is otherwise present for that column in the statement.
"""
DefaultGenerator.__init__(self, for_update=for_update)
IdentityOptions.__init__(
self,
start=start,
increment=increment,
minvalue=minvalue,
maxvalue=maxvalue,
nominvalue=nominvalue,
nomaxvalue=nomaxvalue,
cycle=cycle,
cache=cache,
order=order,
)
self.name = quoted_name(name, quote)
self.optional = optional
if schema is BLANK_SCHEMA:
self.schema = schema = None
elif metadata is not None and schema is None and metadata.schema:
self.schema = schema = metadata.schema
else:
self.schema = quoted_name(schema, quote_schema)
self.metadata = metadata
self._key = _get_table_key(name, schema)
if metadata:
self._set_metadata(metadata)
@util.memoized_property
def is_callable(self):
return False
@util.memoized_property
def is_clause_element(self):
return False
@util.dependencies("sqlalchemy.sql.functions.func")
def next_value(self, func):
"""Return a :class:`.next_value` function element
which will render the appropriate increment function
for this :class:`.Sequence` within any SQL expression.
"""
return func.next_value(self, bind=self.bind)
def _set_parent(self, column):
super(Sequence, self)._set_parent(column)
column._on_table_attach(self._set_table)
def _set_table(self, column, table):
self._set_metadata(table.metadata)
def _set_metadata(self, metadata):
self.metadata = metadata
self.metadata._sequences[self._key] = self
@property
def bind(self):
if self.metadata:
return self.metadata.bind
else:
return None
def create(self, bind=None, checkfirst=True):
"""Creates this sequence in the database."""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
def drop(self, bind=None, checkfirst=True):
"""Drops this sequence from the database."""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaDropper, self, checkfirst=checkfirst)
def _not_a_column_expr(self):
raise exc.InvalidRequestError(
"This %s cannot be used directly "
"as a column expression. Use func.next_value(sequence) "
"to produce a 'next value' function that's usable "
"as a column element." % self.__class__.__name__
)
@inspection._self_inspects
class FetchedValue(_NotAColumnExpr, SchemaEventTarget):
"""A marker for a transparent database-side default.
Use :class:`.FetchedValue` when the database is configured
to provide some automatic default for a column.
E.g.::
Column('foo', Integer, FetchedValue())
Would indicate that some trigger or default generator
will create a new value for the ``foo`` column during an
INSERT.
.. seealso::
:ref:`triggered_columns`
"""
is_server_default = True
reflected = False
has_argument = False
def __init__(self, for_update=False):
self.for_update = for_update
def _as_for_update(self, for_update):
if for_update == self.for_update:
return self
else:
return self._clone(for_update)
def _clone(self, for_update):
n = self.__class__.__new__(self.__class__)
n.__dict__.update(self.__dict__)
n.__dict__.pop("column", None)
n.for_update = for_update
return n
def _set_parent(self, column):
self.column = column
if self.for_update:
self.column.server_onupdate = self
else:
self.column.server_default = self
def __repr__(self):
return util.generic_repr(self)
class DefaultClause(FetchedValue):
"""A DDL-specified DEFAULT column value.
:class:`.DefaultClause` is a :class:`.FetchedValue`
that also generates a "DEFAULT" clause when
"CREATE TABLE" is emitted.
:class:`.DefaultClause` is generated automatically
whenever the ``server_default``, ``server_onupdate`` arguments of
:class:`_schema.Column` are used. A :class:`.DefaultClause`
can be passed positionally as well.
For example, the following::
Column('foo', Integer, server_default="50")
Is equivalent to::
Column('foo', Integer, DefaultClause("50"))
"""
has_argument = True
def __init__(self, arg, for_update=False, _reflected=False):
util.assert_arg_type(
arg, (util.string_types[0], ClauseElement, TextClause), "arg"
)
super(DefaultClause, self).__init__(for_update)
self.arg = arg
self.reflected = _reflected
def __repr__(self):
return "DefaultClause(%r, for_update=%r)" % (self.arg, self.for_update)
@util.deprecated_cls(
"0.6",
":class:`.PassiveDefault` is deprecated and will be removed in a "
"future release. Please refer to :class:`.DefaultClause`.",
)
class PassiveDefault(DefaultClause):
"""A DDL-specified DEFAULT column value."""
def __init__(self, *arg, **kw):
DefaultClause.__init__(self, *arg, **kw)
class Constraint(DialectKWArgs, SchemaItem):
"""A table-level SQL constraint."""
__visit_name__ = "constraint"
def __init__(
self,
name=None,
deferrable=None,
initially=None,
_create_rule=None,
info=None,
_type_bound=False,
**dialect_kw
):
r"""Create a SQL constraint.
:param name:
Optional, the in-database name of this ``Constraint``.
:param deferrable:
Optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when
issuing DDL for this constraint.
:param initially:
Optional string. If set, emit INITIALLY when issuing DDL
for this constraint.
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
:param _create_rule:
a callable which is passed the DDLCompiler object during
compilation. Returns True or False to signal inline generation of
this Constraint.
The AddConstraint and DropConstraint DDL constructs provide
DDLElement's more comprehensive "conditional DDL" approach that is
passed a database connection when DDL is being issued. _create_rule
is instead called during any CREATE TABLE compilation, where there
may not be any transaction/connection in progress. However, it
allows conditional compilation of the constraint even for backends
which do not support addition of constraints through ALTER TABLE,
which currently includes SQLite.
_create_rule is used by some types to create constraints.
Currently, its call signature is subject to change at any time.
:param \**dialect_kw: Additional keyword arguments are dialect
specific, and passed in the form ``_``. See
the documentation regarding an individual dialect at
:ref:`dialect_toplevel` for detail on documented arguments.
"""
self.name = name
self.deferrable = deferrable
self.initially = initially
if info:
self.info = info
self._create_rule = _create_rule
self._type_bound = _type_bound
util.set_creation_order(self)
self._validate_dialect_kwargs(dialect_kw)
@property
def table(self):
try:
if isinstance(self.parent, Table):
return self.parent
except AttributeError:
pass
raise exc.InvalidRequestError(
"This constraint is not bound to a table. Did you "
"mean to call table.append_constraint(constraint) ?"
)
def _set_parent(self, parent):
self.parent = parent
parent.constraints.add(self)
def copy(self, **kw):
raise NotImplementedError()
def _to_schema_column(element):
if hasattr(element, "__clause_element__"):
element = element.__clause_element__()
if not isinstance(element, Column):
raise exc.ArgumentError("schema.Column object expected")
return element
def _to_schema_column_or_string(element):
if element is None:
return element
elif hasattr(element, "__clause_element__"):
element = element.__clause_element__()
if not isinstance(element, util.string_types + (ColumnElement,)):
msg = "Element %r is not a string name or column element"
raise exc.ArgumentError(msg % element)
return element
class ColumnCollectionMixin(object):
columns = None
"""A :class:`_expression.ColumnCollection` of :class:`_schema.Column`
objects.
This collection represents the columns which are referred to by
this object.
"""
_allow_multiple_tables = False
def __init__(self, *columns, **kw):
_autoattach = kw.pop("_autoattach", True)
self._column_flag = kw.pop("_column_flag", False)
self.columns = ColumnCollection()
self._pending_colargs = [
_to_schema_column_or_string(c) for c in columns
]
if _autoattach and self._pending_colargs:
self._check_attach()
@classmethod
def _extract_col_expression_collection(cls, expressions):
for expr in expressions:
strname = None
column = None
if hasattr(expr, "__clause_element__"):
expr = expr.__clause_element__()
if not isinstance(expr, (ColumnElement, TextClause)):
# this assumes a string
strname = expr
else:
cols = []
visitors.traverse(expr, {}, {"column": cols.append})
if cols:
column = cols[0]
add_element = column if column is not None else strname
yield expr, column, strname, add_element
def _check_attach(self, evt=False):
col_objs = [c for c in self._pending_colargs if isinstance(c, Column)]
cols_w_table = [c for c in col_objs if isinstance(c.table, Table)]
cols_wo_table = set(col_objs).difference(cols_w_table)
if cols_wo_table:
# feature #3341 - place event listeners for Column objects
# such that when all those cols are attached, we autoattach.
assert not evt, "Should not reach here on event call"
# issue #3411 - don't do the per-column auto-attach if some of the
# columns are specified as strings.
has_string_cols = set(
c for c in self._pending_colargs if c is not None
).difference(col_objs)
if not has_string_cols:
def _col_attached(column, table):
# this isinstance() corresponds with the
# isinstance() above; only want to count Table-bound
# columns
if isinstance(table, Table):
cols_wo_table.discard(column)
if not cols_wo_table:
self._check_attach(evt=True)
self._cols_wo_table = cols_wo_table
for col in cols_wo_table:
col._on_table_attach(_col_attached)
return
columns = cols_w_table
tables = {c.table for c in columns}
if len(tables) == 1:
self._set_parent_with_dispatch(tables.pop())
elif len(tables) > 1 and not self._allow_multiple_tables:
table = columns[0].table
others = [c for c in columns[1:] if c.table is not table]
if others:
raise exc.ArgumentError(
"Column(s) %s are not part of table '%s'."
% (
", ".join("'%s'" % c for c in others),
table.description,
)
)
def _col_expressions(self, table):
return [
table.c[col] if isinstance(col, util.string_types) else col
for col in self._pending_colargs
]
def _set_parent(self, table):
for col in self._col_expressions(table):
if col is not None:
self.columns.add(col)
class ColumnCollectionConstraint(ColumnCollectionMixin, Constraint):
"""A constraint that proxies a ColumnCollection."""
def __init__(self, *columns, **kw):
r"""
:param \*columns:
A sequence of column names or Column objects.
:param name:
Optional, the in-database name of this constraint.
:param deferrable:
Optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when
issuing DDL for this constraint.
:param initially:
Optional string. If set, emit INITIALLY when issuing DDL
for this constraint.
:param \**kw: other keyword arguments including dialect-specific
arguments are propagated to the :class:`.Constraint` superclass.
"""
_autoattach = kw.pop("_autoattach", True)
_column_flag = kw.pop("_column_flag", False)
Constraint.__init__(self, **kw)
ColumnCollectionMixin.__init__(
self, *columns, _autoattach=_autoattach, _column_flag=_column_flag
)
columns = None
"""A :class:`_expression.ColumnCollection` representing the set of columns
for this constraint.
"""
def _set_parent(self, table):
Constraint._set_parent(self, table)
ColumnCollectionMixin._set_parent(self, table)
def __contains__(self, x):
return x in self.columns
def copy(self, target_table=None, **kw):
# ticket #5276
constraint_kwargs = {}
for dialect_name in self.dialect_options:
dialect_options = self.dialect_options[dialect_name]._non_defaults
for (
dialect_option_key,
dialect_option_value,
) in dialect_options.items():
constraint_kwargs[
dialect_name + "_" + dialect_option_key
] = dialect_option_value
c = self.__class__(
name=self.name,
deferrable=self.deferrable,
initially=self.initially,
*[
_copy_expression(expr, self.parent, target_table)
for expr in self.columns
],
**constraint_kwargs
)
return self._schema_item_copy(c)
def contains_column(self, col):
"""Return True if this constraint contains the given column.
Note that this object also contains an attribute ``.columns``
which is a :class:`_expression.ColumnCollection` of
:class:`_schema.Column` objects.
"""
return self.columns.contains_column(col)
def __iter__(self):
# inlining of
# return iter(self.columns)
# ColumnCollection->OrderedProperties->OrderedDict
ordered_dict = self.columns._data
return (ordered_dict[key] for key in ordered_dict._list)
def __len__(self):
return len(self.columns._data)
class CheckConstraint(ColumnCollectionConstraint):
"""A table- or column-level CHECK constraint.
Can be included in the definition of a Table or Column.
"""
_allow_multiple_tables = True
@_document_text_coercion(
"sqltext",
":class:`.CheckConstraint`",
":paramref:`.CheckConstraint.sqltext`",
)
def __init__(
self,
sqltext,
name=None,
deferrable=None,
initially=None,
table=None,
info=None,
_create_rule=None,
_autoattach=True,
_type_bound=False,
**kw
):
r"""Construct a CHECK constraint.
:param sqltext:
A string containing the constraint definition, which will be used
verbatim, or a SQL expression construct. If given as a string,
the object is converted to a :func:`_expression.text` object.
If the textual
string includes a colon character, escape this using a backslash::
CheckConstraint(r"foo ~ E'a(?\:b|c)d")
:param name:
Optional, the in-database name of the constraint.
:param deferrable:
Optional bool. If set, emit DEFERRABLE or NOT DEFERRABLE when
issuing DDL for this constraint.
:param initially:
Optional string. If set, emit INITIALLY when issuing DDL
for this constraint.
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
"""
self.sqltext = _literal_as_text(sqltext, allow_coercion_to_text=True)
columns = []
visitors.traverse(self.sqltext, {}, {"column": columns.append})
super(CheckConstraint, self).__init__(
name=name,
deferrable=deferrable,
initially=initially,
_create_rule=_create_rule,
info=info,
_type_bound=_type_bound,
_autoattach=_autoattach,
*columns,
**kw
)
if table is not None:
self._set_parent_with_dispatch(table)
def __visit_name__(self):
if isinstance(self.parent, Table):
return "check_constraint"
else:
return "column_check_constraint"
__visit_name__ = property(__visit_name__)
def copy(self, target_table=None, **kw):
if target_table is not None:
# note that target_table is None for the copy process of
# a column-bound CheckConstraint, so this path is not reached
# in that case.
sqltext = _copy_expression(self.sqltext, self.table, target_table)
else:
sqltext = self.sqltext
c = CheckConstraint(
sqltext,
name=self.name,
initially=self.initially,
deferrable=self.deferrable,
_create_rule=self._create_rule,
table=target_table,
_autoattach=False,
_type_bound=self._type_bound,
)
return self._schema_item_copy(c)
class ForeignKeyConstraint(ColumnCollectionConstraint):
"""A table-level FOREIGN KEY constraint.
Defines a single column or composite FOREIGN KEY ... REFERENCES
constraint. For a no-frills, single column foreign key, adding a
:class:`_schema.ForeignKey` to the definition of a :class:`_schema.Column`
is a
shorthand equivalent for an unnamed, single column
:class:`_schema.ForeignKeyConstraint`.
Examples of foreign key configuration are in :ref:`metadata_foreignkeys`.
"""
__visit_name__ = "foreign_key_constraint"
def __init__(
self,
columns,
refcolumns,
name=None,
onupdate=None,
ondelete=None,
deferrable=None,
initially=None,
use_alter=False,
link_to_name=False,
match=None,
table=None,
info=None,
**dialect_kw
):
r"""Construct a composite-capable FOREIGN KEY.
:param columns: A sequence of local column names. The named columns
must be defined and present in the parent Table. The names should
match the ``key`` given to each column (defaults to the name) unless
``link_to_name`` is True.
:param refcolumns: A sequence of foreign column names or Column
objects. The columns must all be located within the same Table.
:param name: Optional, the in-database name of the key.
:param onupdate: Optional string. If set, emit ON UPDATE when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param ondelete: Optional string. If set, emit ON DELETE when
issuing DDL for this constraint. Typical values include CASCADE,
DELETE and RESTRICT.
:param deferrable: Optional bool. If set, emit DEFERRABLE or NOT
DEFERRABLE when issuing DDL for this constraint.
:param initially: Optional string. If set, emit INITIALLY when
issuing DDL for this constraint.
:param link_to_name: if True, the string name given in ``column`` is
the rendered name of the referenced column, not its locally assigned
``key``.
:param use_alter: If True, do not emit the DDL for this constraint as
part of the CREATE TABLE definition. Instead, generate it via an
ALTER TABLE statement issued after the full collection of tables
have been created, and drop it via an ALTER TABLE statement before
the full collection of tables are dropped.
The use of :paramref:`_schema.ForeignKeyConstraint.use_alter` is
particularly geared towards the case where two or more tables
are established within a mutually-dependent foreign key constraint
relationship; however, the :meth:`_schema.MetaData.create_all` and
:meth:`_schema.MetaData.drop_all`
methods will perform this resolution
automatically, so the flag is normally not needed.
.. versionchanged:: 1.0.0 Automatic resolution of foreign key
cycles has been added, removing the need to use the
:paramref:`_schema.ForeignKeyConstraint.use_alter` in typical use
cases.
.. seealso::
:ref:`use_alter`
:param match: Optional string. If set, emit MATCH when issuing
DDL for this constraint. Typical values include SIMPLE, PARTIAL
and FULL.
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
:param \**dialect_kw: Additional keyword arguments are dialect
specific, and passed in the form ``_``. See
the documentation regarding an individual dialect at
:ref:`dialect_toplevel` for detail on documented arguments.
.. versionadded:: 0.9.2
"""
Constraint.__init__(
self,
name=name,
deferrable=deferrable,
initially=initially,
info=info,
**dialect_kw
)
self.onupdate = onupdate
self.ondelete = ondelete
self.link_to_name = link_to_name
self.use_alter = use_alter
self.match = match
if len(set(columns)) != len(refcolumns):
if len(set(columns)) != len(columns):
# e.g. FOREIGN KEY (a, a) REFERENCES r (b, c)
raise exc.ArgumentError(
"ForeignKeyConstraint with duplicate source column "
"references are not supported."
)
else:
# e.g. FOREIGN KEY (a) REFERENCES r (b, c)
# paraphrasing https://www.postgresql.org/docs/9.2/static/\
# ddl-constraints.html
raise exc.ArgumentError(
"ForeignKeyConstraint number "
"of constrained columns must match the number of "
"referenced columns."
)
# standalone ForeignKeyConstraint - create
# associated ForeignKey objects which will be applied to hosted
# Column objects (in col.foreign_keys), either now or when attached
# to the Table for string-specified names
self.elements = [
ForeignKey(
refcol,
_constraint=self,
name=self.name,
onupdate=self.onupdate,
ondelete=self.ondelete,
use_alter=self.use_alter,
link_to_name=self.link_to_name,
match=self.match,
deferrable=self.deferrable,
initially=self.initially,
**self.dialect_kwargs
)
for refcol in refcolumns
]
ColumnCollectionMixin.__init__(self, *columns)
if table is not None:
if hasattr(self, "parent"):
assert table is self.parent
self._set_parent_with_dispatch(table)
def _append_element(self, column, fk):
self.columns.add(column)
self.elements.append(fk)
columns = None
"""A :class:`_expression.ColumnCollection` representing the set of columns
for this constraint.
"""
elements = None
"""A sequence of :class:`_schema.ForeignKey` objects.
Each :class:`_schema.ForeignKey`
represents a single referring column/referred
column pair.
This collection is intended to be read-only.
"""
@property
def _elements(self):
# legacy - provide a dictionary view of (column_key, fk)
return util.OrderedDict(zip(self.column_keys, self.elements))
@property
def _referred_schema(self):
for elem in self.elements:
return elem._referred_schema
else:
return None
@property
def referred_table(self):
"""The :class:`_schema.Table` object to which this
:class:`_schema.ForeignKeyConstraint` references.
This is a dynamically calculated attribute which may not be available
if the constraint and/or parent table is not yet associated with
a metadata collection that contains the referred table.
.. versionadded:: 1.0.0
"""
return self.elements[0].column.table
def _validate_dest_table(self, table):
table_keys = set([elem._table_key() for elem in self.elements])
if None not in table_keys and len(table_keys) > 1:
elem0, elem1 = sorted(table_keys)[0:2]
raise exc.ArgumentError(
"ForeignKeyConstraint on %s(%s) refers to "
"multiple remote tables: %s and %s"
% (table.fullname, self._col_description, elem0, elem1)
)
@property
def column_keys(self):
"""Return a list of string keys representing the local
columns in this :class:`_schema.ForeignKeyConstraint`.
This list is either the original string arguments sent
to the constructor of the :class:`_schema.ForeignKeyConstraint`,
or if the constraint has been initialized with :class:`_schema.Column`
objects, is the string ``.key`` of each element.
.. versionadded:: 1.0.0
"""
if hasattr(self, "parent"):
return self.columns.keys()
else:
return [
col.key if isinstance(col, ColumnElement) else str(col)
for col in self._pending_colargs
]
@property
def _col_description(self):
return ", ".join(self.column_keys)
def _set_parent(self, table):
Constraint._set_parent(self, table)
try:
ColumnCollectionConstraint._set_parent(self, table)
except KeyError as ke:
util.raise_(
exc.ArgumentError(
"Can't create ForeignKeyConstraint "
"on table '%s': no column "
"named '%s' is present." % (table.description, ke.args[0])
),
from_=ke,
)
for col, fk in zip(self.columns, self.elements):
if not hasattr(fk, "parent") or fk.parent is not col:
fk._set_parent_with_dispatch(col)
self._validate_dest_table(table)
def copy(self, schema=None, target_table=None, **kw):
fkc = ForeignKeyConstraint(
[x.parent.key for x in self.elements],
[
x._get_colspec(
schema=schema,
table_name=target_table.name
if target_table is not None
and x._table_key() == x.parent.table.key
else None,
)
for x in self.elements
],
name=self.name,
onupdate=self.onupdate,
ondelete=self.ondelete,
use_alter=self.use_alter,
deferrable=self.deferrable,
initially=self.initially,
link_to_name=self.link_to_name,
match=self.match,
)
for self_fk, other_fk in zip(self.elements, fkc.elements):
self_fk._schema_item_copy(other_fk)
return self._schema_item_copy(fkc)
class PrimaryKeyConstraint(ColumnCollectionConstraint):
"""A table-level PRIMARY KEY constraint.
The :class:`.PrimaryKeyConstraint` object is present automatically
on any :class:`_schema.Table` object; it is assigned a set of
:class:`_schema.Column` objects corresponding to those marked with
the :paramref:`_schema.Column.primary_key` flag::
>>> my_table = Table('mytable', metadata,
... Column('id', Integer, primary_key=True),
... Column('version_id', Integer, primary_key=True),
... Column('data', String(50))
... )
>>> my_table.primary_key
PrimaryKeyConstraint(
Column('id', Integer(), table=,
primary_key=True, nullable=False),
Column('version_id', Integer(), table=,
primary_key=True, nullable=False)
)
The primary key of a :class:`_schema.Table` can also be specified by using
a :class:`.PrimaryKeyConstraint` object explicitly; in this mode of usage,
the "name" of the constraint can also be specified, as well as other
options which may be recognized by dialects::
my_table = Table('mytable', metadata,
Column('id', Integer),
Column('version_id', Integer),
Column('data', String(50)),
PrimaryKeyConstraint('id', 'version_id',
name='mytable_pk')
)
The two styles of column-specification should generally not be mixed.
An warning is emitted if the columns present in the
:class:`.PrimaryKeyConstraint`
don't match the columns that were marked as ``primary_key=True``, if both
are present; in this case, the columns are taken strictly from the
:class:`.PrimaryKeyConstraint` declaration, and those columns otherwise
marked as ``primary_key=True`` are ignored. This behavior is intended to
be backwards compatible with previous behavior.
.. versionchanged:: 0.9.2 Using a mixture of columns within a
:class:`.PrimaryKeyConstraint` in addition to columns marked as
``primary_key=True`` now emits a warning if the lists don't match.
The ultimate behavior of ignoring those columns marked with the flag
only is currently maintained for backwards compatibility; this warning
may raise an exception in a future release.
For the use case where specific options are to be specified on the
:class:`.PrimaryKeyConstraint`, but the usual style of using
``primary_key=True`` flags is still desirable, an empty
:class:`.PrimaryKeyConstraint` may be specified, which will take on the
primary key column collection from the :class:`_schema.Table` based on the
flags::
my_table = Table('mytable', metadata,
Column('id', Integer, primary_key=True),
Column('version_id', Integer, primary_key=True),
Column('data', String(50)),
PrimaryKeyConstraint(name='mytable_pk',
mssql_clustered=True)
)
.. versionadded:: 0.9.2 an empty :class:`.PrimaryKeyConstraint` may now
be specified for the purposes of establishing keyword arguments with
the constraint, independently of the specification of "primary key"
columns within the :class:`_schema.Table` itself; columns marked as
``primary_key=True`` will be gathered into the empty constraint's
column collection.
"""
__visit_name__ = "primary_key_constraint"
def __init__(self, *columns, **kw):
self._implicit_generated = kw.pop("_implicit_generated", False)
super(PrimaryKeyConstraint, self).__init__(*columns, **kw)
def _set_parent(self, table):
super(PrimaryKeyConstraint, self)._set_parent(table)
if table.primary_key is not self:
table.constraints.discard(table.primary_key)
table.primary_key = self
table.constraints.add(self)
table_pks = [c for c in table.c if c.primary_key]
if (
self.columns
and table_pks
and set(table_pks) != set(self.columns.values())
):
util.warn(
"Table '%s' specifies columns %s as primary_key=True, "
"not matching locally specified columns %s; setting the "
"current primary key columns to %s. This warning "
"may become an exception in a future release"
% (
table.name,
", ".join("'%s'" % c.name for c in table_pks),
", ".join("'%s'" % c.name for c in self.columns),
", ".join("'%s'" % c.name for c in self.columns),
)
)
table_pks[:] = []
for c in self.columns:
c.primary_key = True
c.nullable = False
self.columns.extend(table_pks)
def _reload(self, columns):
"""repopulate this :class:`.PrimaryKeyConstraint` given
a set of columns.
Existing columns in the table that are marked as primary_key=True
are maintained.
Also fires a new event.
This is basically like putting a whole new
:class:`.PrimaryKeyConstraint` object on the parent
:class:`_schema.Table` object without actually replacing the object.
The ordering of the given list of columns is also maintained; these
columns will be appended to the list of columns after any which
are already present.
"""
# set the primary key flag on new columns.
# note any existing PK cols on the table also have their
# flag still set.
for col in columns:
col.primary_key = True
self.columns.extend(columns)
PrimaryKeyConstraint._autoincrement_column._reset(self)
self._set_parent_with_dispatch(self.table)
def _replace(self, col):
PrimaryKeyConstraint._autoincrement_column._reset(self)
self.columns.replace(col)
self.dispatch._sa_event_column_added_to_pk_constraint(self, col)
@property
def columns_autoinc_first(self):
autoinc = self._autoincrement_column
if autoinc is not None:
return [autoinc] + [c for c in self.columns if c is not autoinc]
else:
return list(self.columns)
@util.memoized_property
def _autoincrement_column(self):
def _validate_autoinc(col, autoinc_true):
if col.type._type_affinity is None or not issubclass(
col.type._type_affinity, type_api.INTEGERTYPE._type_affinity
):
if autoinc_true:
raise exc.ArgumentError(
"Column type %s on column '%s' is not "
"compatible with autoincrement=True" % (col.type, col)
)
else:
return False
elif (
not isinstance(col.default, (type(None), Sequence))
and not autoinc_true
):
return False
elif col.server_default is not None and not autoinc_true:
return False
elif col.foreign_keys and col.autoincrement not in (
True,
"ignore_fk",
):
return False
return True
if len(self.columns) == 1:
col = list(self.columns)[0]
if col.autoincrement is True:
_validate_autoinc(col, True)
return col
elif (
col.autoincrement
in (
"auto",
"ignore_fk",
)
and _validate_autoinc(col, False)
):
return col
else:
autoinc = None
for col in self.columns:
if col.autoincrement is True:
_validate_autoinc(col, True)
if autoinc is not None:
raise exc.ArgumentError(
"Only one Column may be marked "
"autoincrement=True, found both %s and %s."
% (col.name, autoinc.name)
)
else:
autoinc = col
return autoinc
class UniqueConstraint(ColumnCollectionConstraint):
"""A table-level UNIQUE constraint.
Defines a single column or composite UNIQUE constraint. For a no-frills,
single column constraint, adding ``unique=True`` to the ``Column``
definition is a shorthand equivalent for an unnamed, single column
UniqueConstraint.
"""
__visit_name__ = "unique_constraint"
class Index(DialectKWArgs, ColumnCollectionMixin, SchemaItem):
"""A table-level INDEX.
Defines a composite (one or more column) INDEX.
E.g.::
sometable = Table("sometable", metadata,
Column("name", String(50)),
Column("address", String(100))
)
Index("some_index", sometable.c.name)
For a no-frills, single column index, adding
:class:`_schema.Column` also supports ``index=True``::
sometable = Table("sometable", metadata,
Column("name", String(50), index=True)
)
For a composite index, multiple columns can be specified::
Index("some_index", sometable.c.name, sometable.c.address)
Functional indexes are supported as well, typically by using the
:data:`.func` construct in conjunction with table-bound
:class:`_schema.Column` objects::
Index("some_index", func.lower(sometable.c.name))
An :class:`.Index` can also be manually associated with a
:class:`_schema.Table`,
either through inline declaration or using
:meth:`_schema.Table.append_constraint`. When this approach is used,
the names
of the indexed columns can be specified as strings::
Table("sometable", metadata,
Column("name", String(50)),
Column("address", String(100)),
Index("some_index", "name", "address")
)
To support functional or expression-based indexes in this form, the
:func:`_expression.text` construct may be used::
from sqlalchemy import text
Table("sometable", metadata,
Column("name", String(50)),
Column("address", String(100)),
Index("some_index", text("lower(name)"))
)
.. versionadded:: 0.9.5 the :func:`_expression.text`
construct may be used to
specify :class:`.Index` expressions, provided the :class:`.Index`
is explicitly associated with the :class:`_schema.Table`.
.. seealso::
:ref:`schema_indexes` - General information on :class:`.Index`.
:ref:`postgresql_indexes` - PostgreSQL-specific options available for
the :class:`.Index` construct.
:ref:`mysql_indexes` - MySQL-specific options available for the
:class:`.Index` construct.
:ref:`mssql_indexes` - MSSQL-specific options available for the
:class:`.Index` construct.
"""
__visit_name__ = "index"
def __init__(self, name, *expressions, **kw):
r"""Construct an index object.
:param name:
The name of the index
:param \*expressions:
Column expressions to include in the index. The expressions
are normally instances of :class:`_schema.Column`, but may also
be arbitrary SQL expressions which ultimately refer to a
:class:`_schema.Column`.
:param unique=False:
Keyword only argument; if True, create a unique index.
:param quote=None:
Keyword only argument; whether to apply quoting to the name of
the index. Works in the same manner as that of
:paramref:`_schema.Column.quote`.
:param info=None: Optional data dictionary which will be populated
into the :attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
:param \**kw: Additional keyword arguments not mentioned above are
dialect specific, and passed in the form
``_``. See the documentation regarding an
individual dialect at :ref:`dialect_toplevel` for detail on
documented arguments.
"""
self.table = table = None
columns = []
processed_expressions = []
for (
expr,
column,
strname,
add_element,
) in self._extract_col_expression_collection(expressions):
columns.append(add_element)
processed_expressions.append(expr)
self.expressions = processed_expressions
self.name = quoted_name(name, kw.pop("quote", None))
self.unique = kw.pop("unique", False)
_column_flag = kw.pop("_column_flag", False)
if "info" in kw:
self.info = kw.pop("info")
# TODO: consider "table" argument being public, but for
# the purpose of the fix here, it starts as private.
if "_table" in kw:
table = kw.pop("_table")
self._validate_dialect_kwargs(kw)
# will call _set_parent() if table-bound column
# objects are present
ColumnCollectionMixin.__init__(
self, *columns, _column_flag=_column_flag
)
if table is not None:
self._set_parent(table)
def _set_parent(self, table):
ColumnCollectionMixin._set_parent(self, table)
if self.table is not None and table is not self.table:
raise exc.ArgumentError(
"Index '%s' is against table '%s', and "
"cannot be associated with table '%s'."
% (self.name, self.table.description, table.description)
)
self.table = table
table.indexes.add(self)
expressions = self.expressions
col_expressions = self._col_expressions(table)
assert len(expressions) == len(col_expressions)
self.expressions = [
expr if isinstance(expr, ClauseElement) else colexpr
for expr, colexpr in zip(expressions, col_expressions)
]
@property
def bind(self):
"""Return the connectable associated with this Index."""
return self.table.bind
def create(self, bind=None):
"""Issue a ``CREATE`` statement for this
:class:`.Index`, using the given :class:`.Connectable`
for connectivity.
.. seealso::
:meth:`_schema.MetaData.create_all`.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaGenerator, self)
return self
def drop(self, bind=None):
"""Issue a ``DROP`` statement for this
:class:`.Index`, using the given :class:`.Connectable`
for connectivity.
.. seealso::
:meth:`_schema.MetaData.drop_all`.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(ddl.SchemaDropper, self)
def __repr__(self):
return "Index(%s)" % (
", ".join(
[repr(self.name)]
+ [repr(e) for e in self.expressions]
+ (self.unique and ["unique=True"] or [])
)
)
DEFAULT_NAMING_CONVENTION = util.immutabledict({"ix": "ix_%(column_0_label)s"})
class MetaData(SchemaItem):
"""A collection of :class:`_schema.Table`
objects and their associated schema
constructs.
Holds a collection of :class:`_schema.Table` objects as well as
an optional binding to an :class:`_engine.Engine` or
:class:`_engine.Connection`. If bound, the :class:`_schema.Table` objects
in the collection and their columns may participate in implicit SQL
execution.
The :class:`_schema.Table` objects themselves are stored in the
:attr:`_schema.MetaData.tables` dictionary.
:class:`_schema.MetaData` is a thread-safe object for read operations.
Construction of new tables within a single :class:`_schema.MetaData`
object,
either explicitly or via reflection, may not be completely thread-safe.
.. seealso::
:ref:`metadata_describing` - Introduction to database metadata
"""
__visit_name__ = "metadata"
@util.deprecated_params(
reflect=(
"0.8",
"The :paramref:`_schema.MetaData.reflect` "
"flag is deprecated and will "
"be removed in a future release. Please use the "
":meth:`_schema.MetaData.reflect` method.",
)
)
def __init__(
self,
bind=None,
reflect=False,
schema=None,
quote_schema=None,
naming_convention=None,
info=None,
):
"""Create a new MetaData object.
:param bind:
An Engine or Connection to bind to. May also be a string or URL
instance, these are passed to :func:`_sa.create_engine` and
this :class:`_schema.MetaData` will
be bound to the resulting engine.
:param reflect:
Optional, automatically load all tables from the bound database.
Defaults to False. :paramref:`_schema.MetaData.bind` is required
when this option is set.
:param schema:
The default schema to use for the :class:`_schema.Table`,
:class:`.Sequence`, and potentially other objects associated with
this :class:`_schema.MetaData`. Defaults to ``None``.
When this value is set, any :class:`_schema.Table` or
:class:`.Sequence`
which specifies ``None`` for the schema parameter will instead
have this schema name defined. To build a :class:`_schema.Table`
or :class:`.Sequence` that still has ``None`` for the schema
even when this parameter is present, use the :attr:`.BLANK_SCHEMA`
symbol.
.. note::
As referred above, the :paramref:`_schema.MetaData.schema`
parameter
only refers to the **default value** that will be applied to
the :paramref:`_schema.Table.schema` parameter of an incoming
:class:`_schema.Table` object. It does not refer to how the
:class:`_schema.Table` is catalogued within the
:class:`_schema.MetaData`,
which remains consistent vs. a :class:`_schema.MetaData`
collection
that does not define this parameter. The
:class:`_schema.Table`
within the :class:`_schema.MetaData`
will still be keyed based on its
schema-qualified name, e.g.
``my_metadata.tables["some_schema.my_table"]``.
The current behavior of the :class:`_schema.ForeignKey`
object is to
circumvent this restriction, where it can locate a table given
the table name alone, where the schema will be assumed to be
present from this value as specified on the owning
:class:`_schema.MetaData` collection. However,
this implies that a
table qualified with BLANK_SCHEMA cannot currently be referred
to by string name from :class:`_schema.ForeignKey`.
Other parts of
SQLAlchemy such as Declarative may not have similar behaviors
built in, however may do so in a future release, along with a
consistent method of referring to a table in BLANK_SCHEMA.
.. seealso::
:paramref:`_schema.Table.schema`
:paramref:`.Sequence.schema`
:param quote_schema:
Sets the ``quote_schema`` flag for those :class:`_schema.Table`,
:class:`.Sequence`, and other objects which make usage of the
local ``schema`` name.
:param info: Optional data dictionary which will be populated into the
:attr:`.SchemaItem.info` attribute of this object.
.. versionadded:: 1.0.0
:param naming_convention: a dictionary referring to values which
will establish default naming conventions for :class:`.Constraint`
and :class:`.Index` objects, for those objects which are not given
a name explicitly.
The keys of this dictionary may be:
* a constraint or Index class, e.g. the :class:`.UniqueConstraint`,
:class:`_schema.ForeignKeyConstraint` class, the :class:`.Index`
class
* a string mnemonic for one of the known constraint classes;
``"fk"``, ``"pk"``, ``"ix"``, ``"ck"``, ``"uq"`` for foreign key,
primary key, index, check, and unique constraint, respectively.
* the string name of a user-defined "token" that can be used
to define new naming tokens.
The values associated with each "constraint class" or "constraint
mnemonic" key are string naming templates, such as
``"uq_%(table_name)s_%(column_0_name)s"``,
which describe how the name should be composed. The values
associated with user-defined "token" keys should be callables of the
form ``fn(constraint, table)``, which accepts the constraint/index
object and :class:`_schema.Table` as arguments, returning a string
result.
The built-in names are as follows, some of which may only be
available for certain types of constraint:
* ``%(table_name)s`` - the name of the :class:`_schema.Table`
object
associated with the constraint.
* ``%(referred_table_name)s`` - the name of the
:class:`_schema.Table`
object associated with the referencing target of a
:class:`_schema.ForeignKeyConstraint`.
* ``%(column_0_name)s`` - the name of the :class:`_schema.Column`
at
index position "0" within the constraint.
* ``%(column_0N_name)s`` - the name of all :class:`_schema.Column`
objects in order within the constraint, joined without a
separator.
* ``%(column_0_N_name)s`` - the name of all
:class:`_schema.Column`
objects in order within the constraint, joined with an
underscore as a separator.
* ``%(column_0_label)s``, ``%(column_0N_label)s``,
``%(column_0_N_label)s`` - the label of either the zeroth
:class:`_schema.Column` or all :class:`.Columns`, separated with
or without an underscore
* ``%(column_0_key)s``, ``%(column_0N_key)s``,
``%(column_0_N_key)s`` - the key of either the zeroth
:class:`_schema.Column` or all :class:`.Columns`, separated with
or without an underscore
* ``%(referred_column_0_name)s``, ``%(referred_column_0N_name)s``
``%(referred_column_0_N_name)s``, ``%(referred_column_0_key)s``,
``%(referred_column_0N_key)s``, ... column tokens which
render the names/keys/labels of columns that are referenced
by a :class:`_schema.ForeignKeyConstraint`.
* ``%(constraint_name)s`` - a special key that refers to the
existing name given to the constraint. When this key is
present, the :class:`.Constraint` object's existing name will be
replaced with one that is composed from template string that
uses this token. When this token is present, it is required that
the :class:`.Constraint` is given an explicit name ahead of time.
* user-defined: any additional token may be implemented by passing
it along with a ``fn(constraint, table)`` callable to the
naming_convention dictionary.
.. versionadded:: 1.3.0 - added new ``%(column_0N_name)s``,
``%(column_0_N_name)s``, and related tokens that produce
concatenations of names, keys, or labels for all columns referred
to by a given constraint.
.. seealso::
:ref:`constraint_naming_conventions` - for detailed usage
examples.
"""
self.tables = util.immutabledict()
self.schema = quoted_name(schema, quote_schema)
self.naming_convention = (
naming_convention
if naming_convention
else DEFAULT_NAMING_CONVENTION
)
if info:
self.info = info
self._schemas = set()
self._sequences = {}
self._fk_memos = collections.defaultdict(list)
self.bind = bind
if reflect:
if not bind:
raise exc.ArgumentError(
"A bind must be supplied in conjunction "
"with reflect=True"
)
self.reflect()
tables = None
"""A dictionary of :class:`_schema.Table`
objects keyed to their name or "table key".
The exact key is that determined by the :attr:`_schema.Table.key`
attribute;
for a table with no :attr:`_schema.Table.schema` attribute,
this is the same
as :attr:`_schema.Table.name`. For a table with a schema,
it is typically of the
form ``schemaname.tablename``.
.. seealso::
:attr:`_schema.MetaData.sorted_tables`
"""
def __repr__(self):
return "MetaData(bind=%r)" % self.bind
def __contains__(self, table_or_key):
if not isinstance(table_or_key, util.string_types):
table_or_key = table_or_key.key
return table_or_key in self.tables
def _add_table(self, name, schema, table):
key = _get_table_key(name, schema)
dict.__setitem__(self.tables, key, table)
if schema:
self._schemas.add(schema)
def _remove_table(self, name, schema):
key = _get_table_key(name, schema)
removed = dict.pop(self.tables, key, None)
if removed is not None:
for fk in removed.foreign_keys:
fk._remove_from_metadata(self)
if self._schemas:
self._schemas = set(
[
t.schema
for t in self.tables.values()
if t.schema is not None
]
)
def __getstate__(self):
return {
"tables": self.tables,
"schema": self.schema,
"schemas": self._schemas,
"sequences": self._sequences,
"fk_memos": self._fk_memos,
"naming_convention": self.naming_convention,
}
def __setstate__(self, state):
self.tables = state["tables"]
self.schema = state["schema"]
self.naming_convention = state["naming_convention"]
self._bind = None
self._sequences = state["sequences"]
self._schemas = state["schemas"]
self._fk_memos = state["fk_memos"]
def is_bound(self):
"""True if this MetaData is bound to an Engine or Connection."""
return self._bind is not None
def bind(self):
"""An :class:`_engine.Engine` or :class:`_engine.Connection`
to which this
:class:`_schema.MetaData` is bound.
Typically, a :class:`_engine.Engine` is assigned to this attribute
so that "implicit execution" may be used, or alternatively
as a means of providing engine binding information to an
ORM :class:`.Session` object::
engine = create_engine("someurl://")
metadata.bind = engine
.. seealso::
:ref:`dbengine_implicit` - background on "bound metadata"
"""
return self._bind
@util.dependencies("sqlalchemy.engine.url")
def _bind_to(self, url, bind):
"""Bind this MetaData to an Engine, Connection, string or URL."""
if isinstance(bind, util.string_types + (url.URL,)):
self._bind = sqlalchemy.create_engine(bind)
else:
self._bind = bind
bind = property(bind, _bind_to)
def clear(self):
"""Clear all Table objects from this MetaData."""
dict.clear(self.tables)
self._schemas.clear()
self._fk_memos.clear()
def remove(self, table):
"""Remove the given Table object from this MetaData."""
self._remove_table(table.name, table.schema)
@property
def sorted_tables(self):
"""Returns a list of :class:`_schema.Table` objects sorted in order of
foreign key dependency.
The sorting will place :class:`_schema.Table`
objects that have dependencies
first, before the dependencies themselves, representing the
order in which they can be created. To get the order in which
the tables would be dropped, use the ``reversed()`` Python built-in.
.. warning::
The :attr:`.MetaData.sorted_tables` attribute cannot by itself
accommodate automatic resolution of dependency cycles between
tables, which are usually caused by mutually dependent foreign key
constraints. When these cycles are detected, the foreign keys
of these tables are omitted from consideration in the sort.
A warning is emitted when this condition occurs, which will be an
exception raise in a future release. Tables which are not part
of the cycle will still be returned in dependency order.
To resolve these cycles, the
:paramref:`_schema.ForeignKeyConstraint.use_alter` parameter may be
applied to those constraints which create a cycle. Alternatively,
the :func:`_schema.sort_tables_and_constraints` function will
automatically return foreign key constraints in a separate
collection when cycles are detected so that they may be applied
to a schema separately.
.. versionchanged:: 1.3.17 - a warning is emitted when
:attr:`.MetaData.sorted_tables` cannot perform a proper sort
due to cyclical dependencies. This will be an exception in a
future release. Additionally, the sort will continue to return
other tables not involved in the cycle in dependency order which
was not the case previously.
.. seealso::
:func:`_schema.sort_tables`
:func:`_schema.sort_tables_and_constraints`
:attr:`_schema.MetaData.tables`
:meth:`_reflection.Inspector.get_table_names`
:meth:`_reflection.Inspector.get_sorted_table_and_fkc_names`
"""
return ddl.sort_tables(
sorted(self.tables.values(), key=lambda t: t.key)
)
def reflect(
self,
bind=None,
schema=None,
views=False,
only=None,
extend_existing=False,
autoload_replace=True,
resolve_fks=True,
**dialect_kwargs
):
r"""Load all available table definitions from the database.
Automatically creates ``Table`` entries in this ``MetaData`` for any
table available in the database but not yet present in the
``MetaData``. May be called multiple times to pick up tables recently
added to the database, however no special action is taken if a table
in this ``MetaData`` no longer exists in the database.
:param bind:
A :class:`.Connectable` used to access the database; if None, uses
the existing bind on this ``MetaData``, if any.
:param schema:
Optional, query and reflect tables from an alternate schema.
If None, the schema associated with this :class:`_schema.MetaData`
is used, if any.
:param views:
If True, also reflect views.
:param only:
Optional. Load only a sub-set of available named tables. May be
specified as a sequence of names or a callable.
If a sequence of names is provided, only those tables will be
reflected. An error is raised if a table is requested but not
available. Named tables already present in this ``MetaData`` are
ignored.
If a callable is provided, it will be used as a boolean predicate to
filter the list of potential table names. The callable is called
with a table name and this ``MetaData`` instance as positional
arguments and should return a true value for any table to reflect.
:param extend_existing: Passed along to each :class:`_schema.Table` as
:paramref:`_schema.Table.extend_existing`.
.. versionadded:: 0.9.1
:param autoload_replace: Passed along to each :class:`_schema.Table`
as
:paramref:`_schema.Table.autoload_replace`.
.. versionadded:: 0.9.1
:param resolve_fks: if True, reflect :class:`_schema.Table`
objects linked
to :class:`_schema.ForeignKey` objects located in each
:class:`_schema.Table`.
For :meth:`_schema.MetaData.reflect`,
this has the effect of reflecting
related tables that might otherwise not be in the list of tables
being reflected, for example if the referenced table is in a
different schema or is omitted via the
:paramref:`.MetaData.reflect.only` parameter. When False,
:class:`_schema.ForeignKey` objects are not followed to the
:class:`_schema.Table`
in which they link, however if the related table is also part of the
list of tables that would be reflected in any case, the
:class:`_schema.ForeignKey` object will still resolve to its related
:class:`_schema.Table` after the :meth:`_schema.MetaData.reflect`
operation is
complete. Defaults to True.
.. versionadded:: 1.3.0
.. seealso::
:paramref:`_schema.Table.resolve_fks`
:param \**dialect_kwargs: Additional keyword arguments not mentioned
above are dialect specific, and passed in the form
``_``. See the documentation regarding an
individual dialect at :ref:`dialect_toplevel` for detail on
documented arguments.
.. versionadded:: 0.9.2 - Added
:paramref:`.MetaData.reflect.**dialect_kwargs` to support
dialect-level reflection options for all :class:`_schema.Table`
objects reflected.
"""
if bind is None:
bind = _bind_or_error(self)
with bind.connect() as conn:
reflect_opts = {
"autoload": True,
"autoload_with": conn,
"extend_existing": extend_existing,
"autoload_replace": autoload_replace,
"resolve_fks": resolve_fks,
"_extend_on": set(),
}
reflect_opts.update(dialect_kwargs)
if schema is None:
schema = self.schema
if schema is not None:
reflect_opts["schema"] = schema
available = util.OrderedSet(
bind.engine.table_names(schema, connection=conn)
)
if views:
available.update(bind.dialect.get_view_names(conn, schema))
if schema is not None:
available_w_schema = util.OrderedSet(
["%s.%s" % (schema, name) for name in available]
)
else:
available_w_schema = available
current = set(self.tables)
if only is None:
load = [
name
for name, schname in zip(available, available_w_schema)
if extend_existing or schname not in current
]
elif util.callable(only):
load = [
name
for name, schname in zip(available, available_w_schema)
if (extend_existing or schname not in current)
and only(name, self)
]
else:
missing = [name for name in only if name not in available]
if missing:
s = schema and (" schema '%s'" % schema) or ""
raise exc.InvalidRequestError(
"Could not reflect: requested table(s) not available "
"in %r%s: (%s)" % (bind.engine, s, ", ".join(missing))
)
load = [
name
for name in only
if extend_existing or name not in current
]
for name in load:
try:
Table(name, self, **reflect_opts)
except exc.UnreflectableTableError as uerr:
util.warn("Skipping table %s: %s" % (name, uerr))
@util.deprecated(
"0.7",
"the :meth:`_schema.MetaData.append_ddl_listener` "
"method is deprecated and "
"will be removed in a future release. Please refer to "
":class:`.DDLEvents`.",
)
def append_ddl_listener(self, event_name, listener):
"""Append a DDL event listener to this ``MetaData``."""
def adapt_listener(target, connection, **kw):
tables = kw["tables"]
listener(event, target, connection, tables=tables)
event.listen(self, "" + event_name.replace("-", "_"), adapt_listener)
def create_all(self, bind=None, tables=None, checkfirst=True):
"""Create all tables stored in this metadata.
Conditional by default, will not attempt to recreate tables already
present in the target database.
:param bind:
A :class:`.Connectable` used to access the
database; if None, uses the existing bind on this ``MetaData``, if
any.
:param tables:
Optional list of ``Table`` objects, which is a subset of the total
tables in the ``MetaData`` (others are ignored).
:param checkfirst:
Defaults to True, don't issue CREATEs for tables already present
in the target database.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(
ddl.SchemaGenerator, self, checkfirst=checkfirst, tables=tables
)
def drop_all(self, bind=None, tables=None, checkfirst=True):
"""Drop all tables stored in this metadata.
Conditional by default, will not attempt to drop tables not present in
the target database.
:param bind:
A :class:`.Connectable` used to access the
database; if None, uses the existing bind on this ``MetaData``, if
any.
:param tables:
Optional list of ``Table`` objects, which is a subset of the
total tables in the ``MetaData`` (others are ignored).
:param checkfirst:
Defaults to True, only issue DROPs for tables confirmed to be
present in the target database.
"""
if bind is None:
bind = _bind_or_error(self)
bind._run_visitor(
ddl.SchemaDropper, self, checkfirst=checkfirst, tables=tables
)
class ThreadLocalMetaData(MetaData):
"""A MetaData variant that presents a different ``bind`` in every thread.
Makes the ``bind`` property of the MetaData a thread-local value, allowing
this collection of tables to be bound to different ``Engine``
implementations or connections in each thread.
The ThreadLocalMetaData starts off bound to None in each thread. Binds
must be made explicitly by assigning to the ``bind`` property or using
``connect()``. You can also re-bind dynamically multiple times per
thread, just like a regular ``MetaData``.
"""
__visit_name__ = "metadata"
def __init__(self):
"""Construct a ThreadLocalMetaData."""
self.context = util.threading.local()
self.__engines = {}
super(ThreadLocalMetaData, self).__init__()
def bind(self):
"""The bound Engine or Connection for this thread.
This property may be assigned an Engine or Connection, or assigned a
string or URL to automatically create a basic Engine for this bind
with ``create_engine()``."""
return getattr(self.context, "_engine", None)
@util.dependencies("sqlalchemy.engine.url")
def _bind_to(self, url, bind):
"""Bind to a Connectable in the caller's thread."""
if isinstance(bind, util.string_types + (url.URL,)):
try:
self.context._engine = self.__engines[bind]
except KeyError:
e = sqlalchemy.create_engine(bind)
self.__engines[bind] = e
self.context._engine = e
else:
# TODO: this is squirrely. we shouldn't have to hold onto engines
# in a case like this
if bind not in self.__engines:
self.__engines[bind] = bind
self.context._engine = bind
bind = property(bind, _bind_to)
def is_bound(self):
"""True if there is a bind for this thread."""
return (
hasattr(self.context, "_engine")
and self.context._engine is not None
)
def dispose(self):
"""Dispose all bound engines, in all thread contexts."""
for e in self.__engines.values():
if hasattr(e, "dispose"):
e.dispose()
class _SchemaTranslateMap(object):
"""Provide translation of schema names based on a mapping.
Also provides helpers for producing cache keys and optimized
access when no mapping is present.
Used by the :paramref:`.Connection.execution_options.schema_translate_map`
feature.
.. versionadded:: 1.1
"""
__slots__ = "map_", "__call__", "hash_key", "is_default"
_default_schema_getter = operator.attrgetter("schema")
def __init__(self, map_):
self.map_ = map_
if map_ is not None:
def schema_for_object(obj):
effective_schema = self._default_schema_getter(obj)
effective_schema = obj._translate_schema(
effective_schema, map_
)
return effective_schema
self.__call__ = schema_for_object
self.hash_key = ";".join(
"%s=%s" % (k, map_[k]) for k in sorted(map_, key=str)
)
self.is_default = False
else:
self.hash_key = 0
self.__call__ = self._default_schema_getter
self.is_default = True
@classmethod
def _schema_getter(cls, map_):
if map_ is None:
return _default_schema_map
elif isinstance(map_, _SchemaTranslateMap):
return map_
else:
return _SchemaTranslateMap(map_)
_default_schema_map = _SchemaTranslateMap(None)
_schema_getter = _SchemaTranslateMap._schema_getter
class Computed(FetchedValue, SchemaItem):
"""Defines a generated column, i.e. "GENERATED ALWAYS AS" syntax.
The :class:`.Computed` construct is an inline construct added to the
argument list of a :class:`_schema.Column` object::
from sqlalchemy import Computed
Table('square', meta,
Column('side', Float, nullable=False),
Column('area', Float, Computed('side * side'))
)
See the linked documentation below for complete details.
.. versionadded:: 1.3.11
.. seealso::
:ref:`computed_ddl`
"""
__visit_name__ = "computed_column"
@_document_text_coercion(
"sqltext", ":class:`.Computed`", ":paramref:`.Computed.sqltext`"
)
def __init__(self, sqltext, persisted=None):
"""Construct a GENERATED ALWAYS AS DDL construct to accompany a
:class:`_schema.Column`.
:param sqltext:
A string containing the column generation expression, which will be
used verbatim, or a SQL expression construct, such as a
:func:`_expression.text`
object. If given as a string, the object is converted to a
:func:`_expression.text` object.
:param persisted:
Optional, controls how this column should be persisted by the
database. Possible values are:
* ``None``, the default, it will use the default persistence
defined by the database.
* ``True``, will render ``GENERATED ALWAYS AS ... STORED``, or the
equivalent for the target database if supported.
* ``False``, will render ``GENERATED ALWAYS AS ... VIRTUAL``, or
the equivalent for the target database if supported.
Specifying ``True`` or ``False`` may raise an error when the DDL
is emitted to the target database if the database does not support
that persistence option. Leaving this parameter at its default
of ``None`` is guaranteed to succeed for all databases that support
``GENERATED ALWAYS AS``.
"""
self.sqltext = _literal_as_text(sqltext, allow_coercion_to_text=True)
self.persisted = persisted
self.column = None
def _set_parent(self, parent):
if not isinstance(
parent.server_default, (type(None), Computed)
) or not isinstance(parent.server_onupdate, (type(None), Computed)):
raise exc.ArgumentError(
"A generated column cannot specify a server_default or a "
"server_onupdate argument"
)
self.column = parent
parent.computed = self
self.column.server_onupdate = self
self.column.server_default = self
def _as_for_update(self, for_update):
return self
def copy(self, target_table=None, **kw):
sqltext = _copy_expression(
self.sqltext,
self.column.table if self.column is not None else None,
target_table,
)
g = Computed(sqltext, persisted=self.persisted)
return self._schema_item_copy(g)
PK ! U U sqltypes.pynu [ # sql/sqltypes.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""SQL specific types.
"""
import codecs
import datetime as dt
import decimal
import json
from . import elements
from . import operators
from . import type_api
from .base import _bind_or_error
from .base import NO_ARG
from .base import SchemaEventTarget
from .elements import _literal_as_binds
from .elements import _NONE_NAME
from .elements import quoted_name
from .elements import Slice
from .elements import TypeCoerce as type_coerce # noqa
from .type_api import Emulated
from .type_api import NativeForEmulated # noqa
from .type_api import to_instance
from .type_api import TypeDecorator
from .type_api import TypeEngine
from .type_api import Variant
from .. import event
from .. import exc
from .. import inspection
from .. import processors
from .. import util
from ..util import compat
from ..util import langhelpers
from ..util import pickle
if util.jython:
import array
class _LookupExpressionAdapter(object):
"""Mixin expression adaptations based on lookup tables.
These rules are currently used by the numeric, integer and date types
which have detailed cross-expression coercion rules.
"""
@property
def _expression_adaptations(self):
raise NotImplementedError()
class Comparator(TypeEngine.Comparator):
_blank_dict = util.immutabledict()
def _adapt_expression(self, op, other_comparator):
othertype = other_comparator.type._type_affinity
lookup = self.type._expression_adaptations.get(
op, self._blank_dict
).get(othertype, self.type)
if lookup is othertype:
return (op, other_comparator.type)
elif lookup is self.type._type_affinity:
return (op, self.type)
else:
return (op, to_instance(lookup))
comparator_factory = Comparator
class Concatenable(object):
"""A mixin that marks a type as supporting 'concatenation',
typically strings."""
class Comparator(TypeEngine.Comparator):
def _adapt_expression(self, op, other_comparator):
if op is operators.add and isinstance(
other_comparator,
(Concatenable.Comparator, NullType.Comparator),
):
return operators.concat_op, self.expr.type
else:
return super(Concatenable.Comparator, self)._adapt_expression(
op, other_comparator
)
comparator_factory = Comparator
class Indexable(object):
"""A mixin that marks a type as supporting indexing operations,
such as array or JSON structures.
.. versionadded:: 1.1.0
"""
class Comparator(TypeEngine.Comparator):
def _setup_getitem(self, index):
raise NotImplementedError()
def __getitem__(self, index):
(
adjusted_op,
adjusted_right_expr,
result_type,
) = self._setup_getitem(index)
return self.operate(
adjusted_op, adjusted_right_expr, result_type=result_type
)
comparator_factory = Comparator
class String(Concatenable, TypeEngine):
"""The base for all string and character types.
In SQL, corresponds to VARCHAR. Can also take Python unicode objects
and encode to the database's encoding in bind params (and the reverse for
result sets.)
The `length` field is usually required when the `String` type is
used within a CREATE TABLE statement, as VARCHAR requires a length
on most databases.
"""
__visit_name__ = "string"
@util.deprecated_params(
convert_unicode=(
"1.3",
"The :paramref:`.String.convert_unicode` parameter is deprecated "
"and will be removed in a future release. All modern DBAPIs "
"now support Python Unicode directly and this parameter is "
"unnecessary.",
),
unicode_error=(
"1.3",
"The :paramref:`.String.unicode_errors` parameter is deprecated "
"and will be removed in a future release. This parameter is "
"unnecessary for modern Python DBAPIs and degrades performance "
"significantly.",
),
)
def __init__(
self,
length=None,
collation=None,
convert_unicode=False,
unicode_error=None,
_warn_on_bytestring=False,
_expect_unicode=False,
):
"""
Create a string-holding type.
:param length: optional, a length for the column for use in
DDL and CAST expressions. May be safely omitted if no ``CREATE
TABLE`` will be issued. Certain databases may require a
``length`` for use in DDL, and will raise an exception when
the ``CREATE TABLE`` DDL is issued if a ``VARCHAR``
with no length is included. Whether the value is
interpreted as bytes or characters is database specific.
:param collation: Optional, a column-level collation for
use in DDL and CAST expressions. Renders using the
COLLATE keyword supported by SQLite, MySQL, and PostgreSQL.
E.g.::
>>> from sqlalchemy import cast, select, String
>>> print(select([cast('some string', String(collation='utf8'))]))
SELECT CAST(:param_1 AS VARCHAR COLLATE utf8) AS anon_1
:param convert_unicode: When set to ``True``, the
:class:`.String` type will assume that
input is to be passed as Python Unicode objects under Python 2,
and results returned as Python Unicode objects.
In the rare circumstance that the DBAPI does not support
Python unicode under Python 2, SQLAlchemy will use its own
encoder/decoder functionality on strings, referring to the
value of the :paramref:`_sa.create_engine.encoding` parameter
parameter passed to :func:`_sa.create_engine` as the encoding.
For the extremely rare case that Python Unicode
is to be encoded/decoded by SQLAlchemy on a backend
that *does* natively support Python Unicode,
the string value ``"force"`` can be passed here which will
cause SQLAlchemy's encode/decode services to be
used unconditionally.
.. note::
SQLAlchemy's unicode-conversion flags and features only apply
to Python 2; in Python 3, all string objects are Unicode objects.
For this reason, as well as the fact that virtually all modern
DBAPIs now support Unicode natively even under Python 2,
the :paramref:`.String.convert_unicode` flag is inherently a
legacy feature.
.. note::
In the vast majority of cases, the :class:`.Unicode` or
:class:`.UnicodeText` datatypes should be used for a
:class:`_schema.Column` that expects to store non-ascii data.
These
datatypes will ensure that the correct types are used on the
database side as well as set up the correct Unicode behaviors
under Python 2.
.. seealso::
:paramref:`_sa.create_engine.convert_unicode` -
:class:`_engine.Engine`-wide parameter
:param unicode_error: Optional, a method to use to handle Unicode
conversion errors. Behaves like the ``errors`` keyword argument to
the standard library's ``string.decode()`` functions, requires
that :paramref:`.String.convert_unicode` is set to
``"force"``
"""
if unicode_error is not None and convert_unicode != "force":
raise exc.ArgumentError(
"convert_unicode must be 'force' " "when unicode_error is set."
)
self.length = length
self.collation = collation
self._expect_unicode = convert_unicode or _expect_unicode
self._expect_unicode_error = unicode_error
self._warn_on_bytestring = _warn_on_bytestring
def literal_processor(self, dialect):
def process(value):
value = value.replace("'", "''")
if dialect.identifier_preparer._double_percents:
value = value.replace("%", "%%")
return "'%s'" % value
return process
def bind_processor(self, dialect):
if self._expect_unicode or dialect.convert_unicode:
if (
dialect.supports_unicode_binds
and self._expect_unicode != "force"
):
if self._warn_on_bytestring:
def process(value):
if isinstance(value, util.binary_type):
util.warn_limited(
"Unicode type received non-unicode "
"bind param value %r.",
(util.ellipses_string(value),),
)
return value
return process
else:
return None
else:
encoder = codecs.getencoder(dialect.encoding)
warn_on_bytestring = self._warn_on_bytestring
def process(value):
if isinstance(value, util.text_type):
return encoder(value, self._expect_unicode_error)[0]
elif warn_on_bytestring and value is not None:
util.warn_limited(
"Unicode type received non-unicode bind "
"param value %r.",
(util.ellipses_string(value),),
)
return value
return process
else:
return None
def result_processor(self, dialect, coltype):
wants_unicode = self._expect_unicode or dialect.convert_unicode
needs_convert = wants_unicode and (
dialect.returns_unicode_strings is not True
or self._expect_unicode in ("force", "force_nocheck")
)
needs_isinstance = (
needs_convert
and dialect.returns_unicode_strings
and self._expect_unicode != "force_nocheck"
)
if needs_convert:
if needs_isinstance:
return processors.to_conditional_unicode_processor_factory(
dialect.encoding, self._expect_unicode_error
)
else:
return processors.to_unicode_processor_factory(
dialect.encoding, self._expect_unicode_error
)
else:
return None
@property
def python_type(self):
if self._expect_unicode:
return util.text_type
else:
return str
def get_dbapi_type(self, dbapi):
return dbapi.STRING
@classmethod
def _warn_deprecated_unicode(cls):
util.warn_deprecated(
"The convert_unicode on Engine and String as well as the "
"unicode_error flag on String are deprecated. All modern "
"DBAPIs now support Python Unicode natively under Python 2, and "
"under Python 3 all strings are inherently Unicode. These flags "
"will be removed in a future release."
)
class Text(String):
"""A variably sized string type.
In SQL, usually corresponds to CLOB or TEXT. Can also take Python
unicode objects and encode to the database's encoding in bind
params (and the reverse for result sets.) In general, TEXT objects
do not have a length; while some databases will accept a length
argument here, it will be rejected by others.
"""
__visit_name__ = "text"
class Unicode(String):
"""A variable length Unicode string type.
The :class:`.Unicode` type is a :class:`.String` subclass
that assumes input and output as Python ``unicode`` data,
and in that regard is equivalent to the usage of the
``convert_unicode`` flag with the :class:`.String` type.
However, unlike plain :class:`.String`, it also implies an
underlying column type that is explicitly supporting of non-ASCII
data, such as ``NVARCHAR`` on Oracle and SQL Server.
This can impact the output of ``CREATE TABLE`` statements
and ``CAST`` functions at the dialect level, and can
also affect the handling of bound parameters in some
specific DBAPI scenarios.
The encoding used by the :class:`.Unicode` type is usually
determined by the DBAPI itself; most modern DBAPIs
feature support for Python ``unicode`` objects as bound
values and result set values, and the encoding should
be configured as detailed in the notes for the target
DBAPI in the :ref:`dialect_toplevel` section.
For those DBAPIs which do not support, or are not configured
to accommodate Python ``unicode`` objects
directly, SQLAlchemy does the encoding and decoding
outside of the DBAPI. The encoding in this scenario
is determined by the ``encoding`` flag passed to
:func:`_sa.create_engine`.
When using the :class:`.Unicode` type, it is only appropriate
to pass Python ``unicode`` objects, and not plain ``str``.
If a plain ``str`` is passed under Python 2, a warning
is emitted. If you notice your application emitting these warnings but
you're not sure of the source of them, the Python
``warnings`` filter, documented at
http://docs.python.org/library/warnings.html,
can be used to turn these warnings into exceptions
which will illustrate a stack trace::
import warnings
warnings.simplefilter('error')
For an application that wishes to pass plain bytestrings
and Python ``unicode`` objects to the ``Unicode`` type
equally, the bytestrings must first be decoded into
unicode. The recipe at :ref:`coerce_to_unicode` illustrates
how this is done.
.. seealso::
:class:`.UnicodeText` - unlengthed textual counterpart
to :class:`.Unicode`.
"""
__visit_name__ = "unicode"
def __init__(self, length=None, **kwargs):
"""
Create a :class:`.Unicode` object.
Parameters are the same as that of :class:`.String`,
with the exception that ``convert_unicode``
defaults to ``True``.
"""
kwargs.setdefault("_expect_unicode", True)
kwargs.setdefault("_warn_on_bytestring", True)
super(Unicode, self).__init__(length=length, **kwargs)
class UnicodeText(Text):
"""An unbounded-length Unicode string type.
See :class:`.Unicode` for details on the unicode
behavior of this object.
Like :class:`.Unicode`, usage the :class:`.UnicodeText` type implies a
unicode-capable type being used on the backend, such as
``NCLOB``, ``NTEXT``.
"""
__visit_name__ = "unicode_text"
def __init__(self, length=None, **kwargs):
"""
Create a Unicode-converting Text type.
Parameters are the same as that of :class:`_expression.TextClause`,
with the exception that ``convert_unicode``
defaults to ``True``.
"""
kwargs.setdefault("_expect_unicode", True)
kwargs.setdefault("_warn_on_bytestring", True)
super(UnicodeText, self).__init__(length=length, **kwargs)
def _warn_deprecated_unicode(self):
pass
class Integer(_LookupExpressionAdapter, TypeEngine):
"""A type for ``int`` integers."""
__visit_name__ = "integer"
def get_dbapi_type(self, dbapi):
return dbapi.NUMBER
@property
def python_type(self):
return int
def literal_processor(self, dialect):
def process(value):
return str(value)
return process
@util.memoized_property
def _expression_adaptations(self):
# TODO: need a dictionary object that will
# handle operators generically here, this is incomplete
return {
operators.add: {
Date: Date,
Integer: self.__class__,
Numeric: Numeric,
},
operators.mul: {
Interval: Interval,
Integer: self.__class__,
Numeric: Numeric,
},
operators.div: {Integer: self.__class__, Numeric: Numeric},
operators.truediv: {Integer: self.__class__, Numeric: Numeric},
operators.sub: {Integer: self.__class__, Numeric: Numeric},
}
class SmallInteger(Integer):
"""A type for smaller ``int`` integers.
Typically generates a ``SMALLINT`` in DDL, and otherwise acts like
a normal :class:`.Integer` on the Python side.
"""
__visit_name__ = "small_integer"
class BigInteger(Integer):
"""A type for bigger ``int`` integers.
Typically generates a ``BIGINT`` in DDL, and otherwise acts like
a normal :class:`.Integer` on the Python side.
"""
__visit_name__ = "big_integer"
class Numeric(_LookupExpressionAdapter, TypeEngine):
"""A type for fixed precision numbers, such as ``NUMERIC`` or ``DECIMAL``.
This type returns Python ``decimal.Decimal`` objects by default, unless
the :paramref:`.Numeric.asdecimal` flag is set to False, in which case
they are coerced to Python ``float`` objects.
.. note::
The :class:`.Numeric` type is designed to receive data from a database
type that is explicitly known to be a decimal type
(e.g. ``DECIMAL``, ``NUMERIC``, others) and not a floating point
type (e.g. ``FLOAT``, ``REAL``, others).
If the database column on the server is in fact a floating-point
type, such as ``FLOAT`` or ``REAL``, use the :class:`.Float`
type or a subclass, otherwise numeric coercion between
``float``/``Decimal`` may or may not function as expected.
.. note::
The Python ``decimal.Decimal`` class is generally slow
performing; cPython 3.3 has now switched to use the `cdecimal
`_ library natively. For
older Python versions, the ``cdecimal`` library can be patched
into any application where it will replace the ``decimal``
library fully, however this needs to be applied globally and
before any other modules have been imported, as follows::
import sys
import cdecimal
sys.modules["decimal"] = cdecimal
Note that the ``cdecimal`` and ``decimal`` libraries are **not
compatible with each other**, so patching ``cdecimal`` at the
global level is the only way it can be used effectively with
various DBAPIs that hardcode to import the ``decimal`` library.
"""
__visit_name__ = "numeric"
_default_decimal_return_scale = 10
def __init__(
self,
precision=None,
scale=None,
decimal_return_scale=None,
asdecimal=True,
):
"""
Construct a Numeric.
:param precision: the numeric precision for use in DDL ``CREATE
TABLE``.
:param scale: the numeric scale for use in DDL ``CREATE TABLE``.
:param asdecimal: default True. Return whether or not
values should be sent as Python Decimal objects, or
as floats. Different DBAPIs send one or the other based on
datatypes - the Numeric type will ensure that return values
are one or the other across DBAPIs consistently.
:param decimal_return_scale: Default scale to use when converting
from floats to Python decimals. Floating point values will typically
be much longer due to decimal inaccuracy, and most floating point
database types don't have a notion of "scale", so by default the
float type looks for the first ten decimal places when converting.
Specifying this value will override that length. Types which
do include an explicit ".scale" value, such as the base
:class:`.Numeric` as well as the MySQL float types, will use the
value of ".scale" as the default for decimal_return_scale, if not
otherwise specified.
.. versionadded:: 0.9.0
When using the ``Numeric`` type, care should be taken to ensure
that the asdecimal setting is appropriate for the DBAPI in use -
when Numeric applies a conversion from Decimal->float or float->
Decimal, this conversion incurs an additional performance overhead
for all result columns received.
DBAPIs that return Decimal natively (e.g. psycopg2) will have
better accuracy and higher performance with a setting of ``True``,
as the native translation to Decimal reduces the amount of floating-
point issues at play, and the Numeric type itself doesn't need
to apply any further conversions. However, another DBAPI which
returns floats natively *will* incur an additional conversion
overhead, and is still subject to floating point data loss - in
which case ``asdecimal=False`` will at least remove the extra
conversion overhead.
"""
self.precision = precision
self.scale = scale
self.decimal_return_scale = decimal_return_scale
self.asdecimal = asdecimal
@property
def _effective_decimal_return_scale(self):
if self.decimal_return_scale is not None:
return self.decimal_return_scale
elif getattr(self, "scale", None) is not None:
return self.scale
else:
return self._default_decimal_return_scale
def get_dbapi_type(self, dbapi):
return dbapi.NUMBER
def literal_processor(self, dialect):
def process(value):
return str(value)
return process
@property
def python_type(self):
if self.asdecimal:
return decimal.Decimal
else:
return float
def bind_processor(self, dialect):
if dialect.supports_native_decimal:
return None
else:
return processors.to_float
def result_processor(self, dialect, coltype):
if self.asdecimal:
if dialect.supports_native_decimal:
# we're a "numeric", DBAPI will give us Decimal directly
return None
else:
util.warn(
"Dialect %s+%s does *not* support Decimal "
"objects natively, and SQLAlchemy must "
"convert from floating point - rounding "
"errors and other issues may occur. Please "
"consider storing Decimal numbers as strings "
"or integers on this platform for lossless "
"storage." % (dialect.name, dialect.driver)
)
# we're a "numeric", DBAPI returns floats, convert.
return processors.to_decimal_processor_factory(
decimal.Decimal,
self.scale
if self.scale is not None
else self._default_decimal_return_scale,
)
else:
if dialect.supports_native_decimal:
return processors.to_float
else:
return None
@util.memoized_property
def _expression_adaptations(self):
return {
operators.mul: {
Interval: Interval,
Numeric: self.__class__,
Integer: self.__class__,
},
operators.div: {Numeric: self.__class__, Integer: self.__class__},
operators.truediv: {
Numeric: self.__class__,
Integer: self.__class__,
},
operators.add: {Numeric: self.__class__, Integer: self.__class__},
operators.sub: {Numeric: self.__class__, Integer: self.__class__},
}
class Float(Numeric):
"""Type representing floating point types, such as ``FLOAT`` or ``REAL``.
This type returns Python ``float`` objects by default, unless the
:paramref:`.Float.asdecimal` flag is set to True, in which case they
are coerced to ``decimal.Decimal`` objects.
.. note::
The :class:`.Float` type is designed to receive data from a database
type that is explicitly known to be a floating point type
(e.g. ``FLOAT``, ``REAL``, others)
and not a decimal type (e.g. ``DECIMAL``, ``NUMERIC``, others).
If the database column on the server is in fact a Numeric
type, such as ``DECIMAL`` or ``NUMERIC``, use the :class:`.Numeric`
type or a subclass, otherwise numeric coercion between
``float``/``Decimal`` may or may not function as expected.
"""
__visit_name__ = "float"
scale = None
def __init__(
self, precision=None, asdecimal=False, decimal_return_scale=None
):
r"""
Construct a Float.
:param precision: the numeric precision for use in DDL ``CREATE
TABLE``.
:param asdecimal: the same flag as that of :class:`.Numeric`, but
defaults to ``False``. Note that setting this flag to ``True``
results in floating point conversion.
:param decimal_return_scale: Default scale to use when converting
from floats to Python decimals. Floating point values will typically
be much longer due to decimal inaccuracy, and most floating point
database types don't have a notion of "scale", so by default the
float type looks for the first ten decimal places when converting.
Specifying this value will override that length. Note that the
MySQL float types, which do include "scale", will use "scale"
as the default for decimal_return_scale, if not otherwise specified.
.. versionadded:: 0.9.0
"""
self.precision = precision
self.asdecimal = asdecimal
self.decimal_return_scale = decimal_return_scale
def result_processor(self, dialect, coltype):
if self.asdecimal:
return processors.to_decimal_processor_factory(
decimal.Decimal, self._effective_decimal_return_scale
)
elif dialect.supports_native_decimal:
return processors.to_float
else:
return None
class DateTime(_LookupExpressionAdapter, TypeEngine):
"""A type for ``datetime.datetime()`` objects.
Date and time types return objects from the Python ``datetime``
module. Most DBAPIs have built in support for the datetime
module, with the noted exception of SQLite. In the case of
SQLite, date and time types are stored as strings which are then
converted back to datetime objects when rows are returned.
For the time representation within the datetime type, some
backends include additional options, such as timezone support and
fractional seconds support. For fractional seconds, use the
dialect-specific datatype, such as :class:`.mysql.TIME`. For
timezone support, use at least the :class:`_types.TIMESTAMP` datatype,
if not the dialect-specific datatype object.
"""
__visit_name__ = "datetime"
def __init__(self, timezone=False):
"""Construct a new :class:`.DateTime`.
:param timezone: boolean. Indicates that the datetime type should
enable timezone support, if available on the
**base date/time-holding type only**. It is recommended
to make use of the :class:`_types.TIMESTAMP` datatype directly when
using this flag, as some databases include separate generic
date/time-holding types distinct from the timezone-capable
TIMESTAMP datatype, such as Oracle.
"""
self.timezone = timezone
def get_dbapi_type(self, dbapi):
return dbapi.DATETIME
@property
def python_type(self):
return dt.datetime
@util.memoized_property
def _expression_adaptations(self):
# Based on http://www.postgresql.org/docs/current/\
# static/functions-datetime.html.
return {
operators.add: {Interval: self.__class__},
operators.sub: {Interval: self.__class__, DateTime: Interval},
}
class Date(_LookupExpressionAdapter, TypeEngine):
"""A type for ``datetime.date()`` objects."""
__visit_name__ = "date"
def get_dbapi_type(self, dbapi):
return dbapi.DATETIME
@property
def python_type(self):
return dt.date
@util.memoized_property
def _expression_adaptations(self):
# Based on http://www.postgresql.org/docs/current/\
# static/functions-datetime.html.
return {
operators.add: {
Integer: self.__class__,
Interval: DateTime,
Time: DateTime,
},
operators.sub: {
# date - integer = date
Integer: self.__class__,
# date - date = integer.
Date: Integer,
Interval: DateTime,
# date - datetime = interval,
# this one is not in the PG docs
# but works
DateTime: Interval,
},
}
class Time(_LookupExpressionAdapter, TypeEngine):
"""A type for ``datetime.time()`` objects."""
__visit_name__ = "time"
def __init__(self, timezone=False):
self.timezone = timezone
def get_dbapi_type(self, dbapi):
return dbapi.DATETIME
@property
def python_type(self):
return dt.time
@util.memoized_property
def _expression_adaptations(self):
# Based on http://www.postgresql.org/docs/current/\
# static/functions-datetime.html.
return {
operators.add: {Date: DateTime, Interval: self.__class__},
operators.sub: {Time: Interval, Interval: self.__class__},
}
class _Binary(TypeEngine):
"""Define base behavior for binary types."""
def __init__(self, length=None):
self.length = length
def literal_processor(self, dialect):
def process(value):
value = value.decode(dialect.encoding).replace("'", "''")
return "'%s'" % value
return process
@property
def python_type(self):
return util.binary_type
# Python 3 - sqlite3 doesn't need the `Binary` conversion
# here, though pg8000 does to indicate "bytea"
def bind_processor(self, dialect):
if dialect.dbapi is None:
return None
DBAPIBinary = dialect.dbapi.Binary
def process(value):
if value is not None:
return DBAPIBinary(value)
else:
return None
return process
# Python 3 has native bytes() type
# both sqlite3 and pg8000 seem to return it,
# psycopg2 as of 2.5 returns 'memoryview'
if util.py2k:
def result_processor(self, dialect, coltype):
if util.jython:
def process(value):
if value is not None:
if isinstance(value, array.array):
return value.tostring()
return str(value)
else:
return None
else:
process = processors.to_str
return process
else:
def result_processor(self, dialect, coltype):
def process(value):
if value is not None:
value = bytes(value)
return value
return process
def coerce_compared_value(self, op, value):
"""See :meth:`.TypeEngine.coerce_compared_value` for a description."""
if isinstance(value, util.string_types):
return self
else:
return super(_Binary, self).coerce_compared_value(op, value)
def get_dbapi_type(self, dbapi):
return dbapi.BINARY
class LargeBinary(_Binary):
"""A type for large binary byte data.
The :class:`.LargeBinary` type corresponds to a large and/or unlengthed
binary type for the target platform, such as BLOB on MySQL and BYTEA for
PostgreSQL. It also handles the necessary conversions for the DBAPI.
"""
__visit_name__ = "large_binary"
def __init__(self, length=None):
"""
Construct a LargeBinary type.
:param length: optional, a length for the column for use in
DDL statements, for those binary types that accept a length,
such as the MySQL BLOB type.
"""
_Binary.__init__(self, length=length)
@util.deprecated_cls(
"0.6",
"The :class:`.Binary` class is deprecated and will be removed "
"in a future relase. Please use :class:`.LargeBinary`.",
)
class Binary(LargeBinary):
def __init__(self, *arg, **kw):
LargeBinary.__init__(self, *arg, **kw)
class SchemaType(SchemaEventTarget):
"""Mark a type as possibly requiring schema-level DDL for usage.
Supports types that must be explicitly created/dropped (i.e. PG ENUM type)
as well as types that are complimented by table or schema level
constraints, triggers, and other rules.
:class:`.SchemaType` classes can also be targets for the
:meth:`.DDLEvents.before_parent_attach` and
:meth:`.DDLEvents.after_parent_attach` events, where the events fire off
surrounding the association of the type object with a parent
:class:`_schema.Column`.
.. seealso::
:class:`.Enum`
:class:`.Boolean`
"""
def __init__(
self,
name=None,
schema=None,
metadata=None,
inherit_schema=False,
quote=None,
_create_events=True,
):
if name is not None:
self.name = quoted_name(name, quote)
else:
self.name = None
self.schema = schema
self.metadata = metadata
self.inherit_schema = inherit_schema
self._create_events = _create_events
if _create_events and self.metadata:
event.listen(
self.metadata,
"before_create",
util.portable_instancemethod(self._on_metadata_create),
)
event.listen(
self.metadata,
"after_drop",
util.portable_instancemethod(self._on_metadata_drop),
)
def _translate_schema(self, effective_schema, map_):
return map_.get(effective_schema, effective_schema)
def _set_parent(self, column, **kw):
column._on_table_attach(util.portable_instancemethod(self._set_table))
def _variant_mapping_for_set_table(self, column):
if isinstance(column.type, Variant):
variant_mapping = column.type.mapping.copy()
variant_mapping["_default"] = column.type.impl
else:
variant_mapping = None
return variant_mapping
def _set_table(self, column, table):
if self.inherit_schema:
self.schema = table.schema
if not self._create_events:
return
variant_mapping = self._variant_mapping_for_set_table(column)
event.listen(
table,
"before_create",
util.portable_instancemethod(
self._on_table_create, {"variant_mapping": variant_mapping}
),
)
event.listen(
table,
"after_drop",
util.portable_instancemethod(
self._on_table_drop, {"variant_mapping": variant_mapping}
),
)
if self.metadata is None:
# TODO: what's the difference between self.metadata
# and table.metadata here ?
event.listen(
table.metadata,
"before_create",
util.portable_instancemethod(
self._on_metadata_create,
{"variant_mapping": variant_mapping},
),
)
event.listen(
table.metadata,
"after_drop",
util.portable_instancemethod(
self._on_metadata_drop,
{"variant_mapping": variant_mapping},
),
)
def copy(self, **kw):
return self.adapt(self.__class__, _create_events=True)
def adapt(self, impltype, **kw):
schema = kw.pop("schema", self.schema)
metadata = kw.pop("metadata", self.metadata)
_create_events = kw.pop("_create_events", False)
return impltype(
name=self.name,
schema=schema,
inherit_schema=self.inherit_schema,
metadata=metadata,
_create_events=_create_events,
**kw
)
@property
def bind(self):
return self.metadata and self.metadata.bind or None
def create(self, bind=None, checkfirst=False):
"""Issue CREATE DDL for this type, if applicable."""
if bind is None:
bind = _bind_or_error(self)
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t.create(bind=bind, checkfirst=checkfirst)
def drop(self, bind=None, checkfirst=False):
"""Issue DROP DDL for this type, if applicable."""
if bind is None:
bind = _bind_or_error(self)
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t.drop(bind=bind, checkfirst=checkfirst)
def _on_table_create(self, target, bind, **kw):
if not self._is_impl_for_variant(bind.dialect, kw):
return
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t._on_table_create(target, bind, **kw)
def _on_table_drop(self, target, bind, **kw):
if not self._is_impl_for_variant(bind.dialect, kw):
return
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t._on_table_drop(target, bind, **kw)
def _on_metadata_create(self, target, bind, **kw):
if not self._is_impl_for_variant(bind.dialect, kw):
return
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t._on_metadata_create(target, bind, **kw)
def _on_metadata_drop(self, target, bind, **kw):
if not self._is_impl_for_variant(bind.dialect, kw):
return
t = self.dialect_impl(bind.dialect)
if t.__class__ is not self.__class__ and isinstance(t, SchemaType):
t._on_metadata_drop(target, bind, **kw)
def _is_impl_for_variant(self, dialect, kw):
variant_mapping = kw.pop("variant_mapping", None)
if variant_mapping is None:
return True
if (
dialect.name in variant_mapping
and variant_mapping[dialect.name] is self
):
return True
elif dialect.name not in variant_mapping:
return variant_mapping["_default"] is self
class Enum(Emulated, String, SchemaType):
"""Generic Enum Type.
The :class:`.Enum` type provides a set of possible string values
which the column is constrained towards.
The :class:`.Enum` type will make use of the backend's native "ENUM"
type if one is available; otherwise, it uses a VARCHAR datatype and
produces a CHECK constraint. Use of the backend-native enum type
can be disabled using the :paramref:`.Enum.native_enum` flag, and
the production of the CHECK constraint is configurable using the
:paramref:`.Enum.create_constraint` flag.
The :class:`.Enum` type also provides in-Python validation of string
values during both read and write operations. When reading a value
from the database in a result set, the string value is always checked
against the list of possible values and a ``LookupError`` is raised
if no match is found. When passing a value to the database as a
plain string within a SQL statement, if the
:paramref:`.Enum.validate_strings` parameter is
set to True, a ``LookupError`` is raised for any string value that's
not located in the given list of possible values; note that this
impacts usage of LIKE expressions with enumerated values (an unusual
use case).
.. versionchanged:: 1.1 the :class:`.Enum` type now provides in-Python
validation of input values as well as on data being returned by
the database.
The source of enumerated values may be a list of string values, or
alternatively a PEP-435-compliant enumerated class. For the purposes
of the :class:`.Enum` datatype, this class need only provide a
``__members__`` method.
When using an enumerated class, the enumerated objects are used
both for input and output, rather than strings as is the case with
a plain-string enumerated type::
import enum
class MyEnum(enum.Enum):
one = 1
two = 2
three = 3
t = Table(
'data', MetaData(),
Column('value', Enum(MyEnum))
)
connection.execute(t.insert(), {"value": MyEnum.two})
assert connection.scalar(t.select()) is MyEnum.two
Above, the string names of each element, e.g. "one", "two", "three",
are persisted to the database; the values of the Python Enum, here
indicated as integers, are **not** used; the value of each enum can
therefore be any kind of Python object whether or not it is persistable.
In order to persist the values and not the names, the
:paramref:`.Enum.values_callable` parameter may be used. The value of
this parameter is a user-supplied callable, which is intended to be used
with a PEP-435-compliant enumerated class and returns a list of string
values to be persisted. For a simple enumeration that uses string values,
a callable such as ``lambda x: [e.value for e in x]`` is sufficient.
.. versionadded:: 1.1 - support for PEP-435-style enumerated
classes.
.. seealso::
:class:`_postgresql.ENUM` - PostgreSQL-specific type,
which has additional functionality.
:class:`.mysql.ENUM` - MySQL-specific type
"""
__visit_name__ = "enum"
@util.deprecated_params(
convert_unicode=(
"1.3",
"The :paramref:`.Enum.convert_unicode` parameter is deprecated "
"and will be removed in a future release. All modern DBAPIs "
"now support Python Unicode directly and this parameter is "
"unnecessary.",
)
)
def __init__(self, *enums, **kw):
r"""Construct an enum.
Keyword arguments which don't apply to a specific backend are ignored
by that backend.
:param \*enums: either exactly one PEP-435 compliant enumerated type
or one or more string or unicode enumeration labels. If unicode
labels are present, the `convert_unicode` flag is auto-enabled.
.. versionadded:: 1.1 a PEP-435 style enumerated class may be
passed.
:param convert_unicode: Enable unicode-aware bind parameter and
result-set processing for this Enum's data. This is set
automatically based on the presence of unicode label strings.
:param create_constraint: defaults to True. When creating a non-native
enumerated type, also build a CHECK constraint on the database
against the valid values.
.. versionadded:: 1.1 - added :paramref:`.Enum.create_constraint`
which provides the option to disable the production of the
CHECK constraint for a non-native enumerated type.
:param metadata: Associate this type directly with a ``MetaData``
object. For types that exist on the target database as an
independent schema construct (PostgreSQL), this type will be
created and dropped within ``create_all()`` and ``drop_all()``
operations. If the type is not associated with any ``MetaData``
object, it will associate itself with each ``Table`` in which it is
used, and will be created when any of those individual tables are
created, after a check is performed for its existence. The type is
only dropped when ``drop_all()`` is called for that ``Table``
object's metadata, however.
:param name: The name of this type. This is required for PostgreSQL
and any future supported database which requires an explicitly
named type, or an explicitly named constraint in order to generate
the type and/or a table that uses it. If a PEP-435 enumerated
class was used, its name (converted to lower case) is used by
default.
:param native_enum: Use the database's native ENUM type when
available. Defaults to True. When False, uses VARCHAR + check
constraint for all backends. The VARCHAR length can be controlled
with :paramref:`.Enum.length`
:param length: Allows specifying a custom length for the VARCHAR
when :paramref:`.Enum.native_enum` is False. By default it uses the
length of the longest value.
.. versionadded:: 1.3.16
:param schema: Schema name of this type. For types that exist on the
target database as an independent schema construct (PostgreSQL),
this parameter specifies the named schema in which the type is
present.
.. note::
The ``schema`` of the :class:`.Enum` type does not
by default make use of the ``schema`` established on the
owning :class:`_schema.Table`. If this behavior is desired,
set the ``inherit_schema`` flag to ``True``.
:param quote: Set explicit quoting preferences for the type's name.
:param inherit_schema: When ``True``, the "schema" from the owning
:class:`_schema.Table`
will be copied to the "schema" attribute of this
:class:`.Enum`, replacing whatever value was passed for the
``schema`` attribute. This also takes effect when using the
:meth:`_schema.Table.tometadata` operation.
:param validate_strings: when True, string values that are being
passed to the database in a SQL statement will be checked
for validity against the list of enumerated values. Unrecognized
values will result in a ``LookupError`` being raised.
.. versionadded:: 1.1.0b2
:param values_callable: A callable which will be passed the PEP-435
compliant enumerated type, which should then return a list of string
values to be persisted. This allows for alternate usages such as
using the string value of an enum to be persisted to the database
instead of its name.
.. versionadded:: 1.2.3
:param sort_key_function: a Python callable which may be used as the
"key" argument in the Python ``sorted()`` built-in. The SQLAlchemy
ORM requires that primary key columns which are mapped must
be sortable in some way. When using an unsortable enumeration
object such as a Python 3 ``Enum`` object, this parameter may be
used to set a default sort key function for the objects. By
default, the database value of the enumeration is used as the
sorting function.
.. versionadded:: 1.3.8
"""
self._enum_init(enums, kw)
@property
def _enums_argument(self):
if self.enum_class is not None:
return [self.enum_class]
else:
return self.enums
def _enum_init(self, enums, kw):
"""internal init for :class:`.Enum` and subclasses.
friendly init helper used by subclasses to remove
all the Enum-specific keyword arguments from kw. Allows all
other arguments in kw to pass through.
"""
self.native_enum = kw.pop("native_enum", True)
self.create_constraint = kw.pop("create_constraint", True)
self.values_callable = kw.pop("values_callable", None)
self._sort_key_function = kw.pop("sort_key_function", NO_ARG)
length_arg = kw.pop("length", NO_ARG)
values, objects = self._parse_into_values(enums, kw)
self._setup_for_values(values, objects, kw)
convert_unicode = kw.pop("convert_unicode", None)
self.validate_strings = kw.pop("validate_strings", False)
if convert_unicode is None:
for e in self.enums:
# this is all py2k logic that can go away for py3k only,
# "expect unicode" will always be implicitly true
if isinstance(e, util.text_type):
_expect_unicode = True
break
else:
_expect_unicode = False
else:
_expect_unicode = convert_unicode
if self.enums:
length = max(len(x) for x in self.enums)
else:
length = 0
if not self.native_enum and length_arg is not NO_ARG:
if length_arg < length:
raise ValueError(
"When provided, length must be larger or equal"
" than the length of the longest enum value. %s < %s"
% (length_arg, length)
)
length = length_arg
self._valid_lookup[None] = self._object_lookup[None] = None
super(Enum, self).__init__(
length=length, _expect_unicode=_expect_unicode
)
if self.enum_class:
kw.setdefault("name", self.enum_class.__name__.lower())
SchemaType.__init__(
self,
name=kw.pop("name", None),
schema=kw.pop("schema", None),
metadata=kw.pop("metadata", None),
inherit_schema=kw.pop("inherit_schema", False),
quote=kw.pop("quote", None),
_create_events=kw.pop("_create_events", True),
)
def _parse_into_values(self, enums, kw):
if not enums and "_enums" in kw:
enums = kw.pop("_enums")
if len(enums) == 1 and hasattr(enums[0], "__members__"):
self.enum_class = enums[0]
members = self.enum_class.__members__
if self.values_callable:
values = self.values_callable(self.enum_class)
else:
values = list(members)
objects = [members[k] for k in members]
return values, objects
else:
self.enum_class = None
return enums, enums
def _setup_for_values(self, values, objects, kw):
self.enums = list(values)
self._valid_lookup = dict(zip(reversed(objects), reversed(values)))
self._object_lookup = dict(zip(values, objects))
self._valid_lookup.update(
[
(value, self._valid_lookup[self._object_lookup[value]])
for value in values
]
)
@property
def sort_key_function(self):
if self._sort_key_function is NO_ARG:
return self._db_value_for_elem
else:
return self._sort_key_function
@property
def native(self):
return self.native_enum
def _db_value_for_elem(self, elem):
try:
return self._valid_lookup[elem]
except KeyError as err:
# for unknown string values, we return as is. While we can
# validate these if we wanted, that does not allow for lesser-used
# end-user use cases, such as using a LIKE comparison with an enum,
# or for an application that wishes to apply string tests to an
# ENUM (see [ticket:3725]). While we can decide to differentiate
# here between an INSERT statement and a criteria used in a SELECT,
# for now we're staying conservative w/ behavioral changes (perhaps
# someone has a trigger that handles strings on INSERT)
if not self.validate_strings and isinstance(
elem, compat.string_types
):
return elem
else:
util.raise_(
LookupError(
"'%s' is not among the defined enum values. "
"Enum name: %s. Possible values: %s"
% (
elem,
self.name,
langhelpers.repr_tuple_names(self.enums),
)
),
replace_context=err,
)
class Comparator(String.Comparator):
def _adapt_expression(self, op, other_comparator):
op, typ = super(Enum.Comparator, self)._adapt_expression(
op, other_comparator
)
if op is operators.concat_op:
typ = String(
self.type.length, _expect_unicode=self.type._expect_unicode
)
return op, typ
comparator_factory = Comparator
def _object_value_for_elem(self, elem):
try:
return self._object_lookup[elem]
except KeyError as err:
util.raise_(
LookupError(
"'%s' is not among the defined enum values. "
"Enum name: %s. Possible values: %s"
% (
elem,
self.name,
langhelpers.repr_tuple_names(self.enums),
)
),
replace_context=err,
)
def __repr__(self):
return util.generic_repr(
self,
additional_kw=[("native_enum", True)],
to_inspect=[Enum, SchemaType],
)
def adapt_to_emulated(self, impltype, **kw):
kw.setdefault("_expect_unicode", self._expect_unicode)
kw.setdefault("validate_strings", self.validate_strings)
kw.setdefault("name", self.name)
kw.setdefault("schema", self.schema)
kw.setdefault("inherit_schema", self.inherit_schema)
kw.setdefault("metadata", self.metadata)
kw.setdefault("_create_events", False)
kw.setdefault("native_enum", self.native_enum)
kw.setdefault("values_callable", self.values_callable)
kw.setdefault("create_constraint", self.create_constraint)
kw.setdefault("length", self.length)
assert "_enums" in kw
return impltype(**kw)
def adapt(self, impltype, **kw):
kw["_enums"] = self._enums_argument
return super(Enum, self).adapt(impltype, **kw)
def _should_create_constraint(self, compiler, **kw):
if not self._is_impl_for_variant(compiler.dialect, kw):
return False
return (
not self.native_enum or not compiler.dialect.supports_native_enum
)
@util.dependencies("sqlalchemy.sql.schema")
def _set_table(self, schema, column, table):
SchemaType._set_table(self, column, table)
if not self.create_constraint:
return
variant_mapping = self._variant_mapping_for_set_table(column)
e = schema.CheckConstraint(
type_coerce(column, self).in_(self.enums),
name=_NONE_NAME if self.name is None else self.name,
_create_rule=util.portable_instancemethod(
self._should_create_constraint,
{"variant_mapping": variant_mapping},
),
_type_bound=True,
)
assert e.table is table
def literal_processor(self, dialect):
parent_processor = super(Enum, self).literal_processor(dialect)
def process(value):
value = self._db_value_for_elem(value)
if parent_processor:
value = parent_processor(value)
return value
return process
def bind_processor(self, dialect):
def process(value):
value = self._db_value_for_elem(value)
if parent_processor:
value = parent_processor(value)
return value
parent_processor = super(Enum, self).bind_processor(dialect)
return process
def result_processor(self, dialect, coltype):
parent_processor = super(Enum, self).result_processor(dialect, coltype)
def process(value):
if parent_processor:
value = parent_processor(value)
value = self._object_value_for_elem(value)
return value
return process
def copy(self, **kw):
return SchemaType.copy(self, **kw)
@property
def python_type(self):
if self.enum_class:
return self.enum_class
else:
return super(Enum, self).python_type
class PickleType(TypeDecorator):
"""Holds Python objects, which are serialized using pickle.
PickleType builds upon the Binary type to apply Python's
``pickle.dumps()`` to incoming objects, and ``pickle.loads()`` on
the way out, allowing any pickleable Python object to be stored as
a serialized binary field.
To allow ORM change events to propagate for elements associated
with :class:`.PickleType`, see :ref:`mutable_toplevel`.
"""
impl = LargeBinary
def __init__(
self, protocol=pickle.HIGHEST_PROTOCOL, pickler=None, comparator=None
):
"""
Construct a PickleType.
:param protocol: defaults to ``pickle.HIGHEST_PROTOCOL``.
:param pickler: defaults to cPickle.pickle or pickle.pickle if
cPickle is not available. May be any object with
pickle-compatible ``dumps`` and ``loads`` methods.
:param comparator: a 2-arg callable predicate used
to compare values of this type. If left as ``None``,
the Python "equals" operator is used to compare values.
"""
self.protocol = protocol
self.pickler = pickler or pickle
self.comparator = comparator
super(PickleType, self).__init__()
def __reduce__(self):
return PickleType, (self.protocol, None, self.comparator)
def bind_processor(self, dialect):
impl_processor = self.impl.bind_processor(dialect)
dumps = self.pickler.dumps
protocol = self.protocol
if impl_processor:
def process(value):
if value is not None:
value = dumps(value, protocol)
return impl_processor(value)
else:
def process(value):
if value is not None:
value = dumps(value, protocol)
return value
return process
def result_processor(self, dialect, coltype):
impl_processor = self.impl.result_processor(dialect, coltype)
loads = self.pickler.loads
if impl_processor:
def process(value):
value = impl_processor(value)
if value is None:
return None
return loads(value)
else:
def process(value):
if value is None:
return None
return loads(value)
return process
def compare_values(self, x, y):
if self.comparator:
return self.comparator(x, y)
else:
return x == y
class Boolean(Emulated, TypeEngine, SchemaType):
"""A bool datatype.
:class:`.Boolean` typically uses BOOLEAN or SMALLINT on the DDL side,
and on the Python side deals in ``True`` or ``False``.
The :class:`.Boolean` datatype currently has two levels of assertion
that the values persisted are simple true/false values. For all
backends, only the Python values ``None``, ``True``, ``False``, ``1``
or ``0`` are accepted as parameter values. For those backends that
don't support a "native boolean" datatype, a CHECK constraint is also
created on the target column. Production of the CHECK constraint
can be disabled by passing the :paramref:`.Boolean.create_constraint`
flag set to ``False``.
.. versionchanged:: 1.2 the :class:`.Boolean` datatype now asserts that
incoming Python values are already in pure boolean form.
"""
__visit_name__ = "boolean"
native = True
def __init__(self, create_constraint=True, name=None, _create_events=True):
"""Construct a Boolean.
:param create_constraint: defaults to True. If the boolean
is generated as an int/smallint, also create a CHECK constraint
on the table that ensures 1 or 0 as a value.
:param name: if a CHECK constraint is generated, specify
the name of the constraint.
"""
self.create_constraint = create_constraint
self.name = name
self._create_events = _create_events
def _should_create_constraint(self, compiler, **kw):
if not self._is_impl_for_variant(compiler.dialect, kw):
return False
return (
not compiler.dialect.supports_native_boolean
and compiler.dialect.non_native_boolean_check_constraint
)
@util.dependencies("sqlalchemy.sql.schema")
def _set_table(self, schema, column, table):
if not self.create_constraint:
return
variant_mapping = self._variant_mapping_for_set_table(column)
e = schema.CheckConstraint(
type_coerce(column, self).in_([0, 1]),
name=_NONE_NAME if self.name is None else self.name,
_create_rule=util.portable_instancemethod(
self._should_create_constraint,
{"variant_mapping": variant_mapping},
),
_type_bound=True,
)
assert e.table is table
@property
def python_type(self):
return bool
_strict_bools = frozenset([None, True, False])
def _strict_as_bool(self, value):
if value not in self._strict_bools:
if not isinstance(value, int):
raise TypeError("Not a boolean value: %r" % value)
else:
raise ValueError(
"Value %r is not None, True, or False" % value
)
return value
def literal_processor(self, dialect):
compiler = dialect.statement_compiler(dialect, None)
true = compiler.visit_true(None)
false = compiler.visit_false(None)
def process(value):
return true if self._strict_as_bool(value) else false
return process
def bind_processor(self, dialect):
_strict_as_bool = self._strict_as_bool
if dialect.supports_native_boolean:
_coerce = bool
else:
_coerce = int
def process(value):
value = _strict_as_bool(value)
if value is not None:
value = _coerce(value)
return value
return process
def result_processor(self, dialect, coltype):
if dialect.supports_native_boolean:
return None
else:
return processors.int_to_boolean
class _AbstractInterval(_LookupExpressionAdapter, TypeEngine):
@util.memoized_property
def _expression_adaptations(self):
# Based on http://www.postgresql.org/docs/current/\
# static/functions-datetime.html.
return {
operators.add: {
Date: DateTime,
Interval: self.__class__,
DateTime: DateTime,
Time: Time,
},
operators.sub: {Interval: self.__class__},
operators.mul: {Numeric: self.__class__},
operators.truediv: {Numeric: self.__class__},
operators.div: {Numeric: self.__class__},
}
@property
def _type_affinity(self):
return Interval
def coerce_compared_value(self, op, value):
"""See :meth:`.TypeEngine.coerce_compared_value` for a description."""
return self.impl.coerce_compared_value(op, value)
class Interval(Emulated, _AbstractInterval, TypeDecorator):
"""A type for ``datetime.timedelta()`` objects.
The Interval type deals with ``datetime.timedelta`` objects. In
PostgreSQL, the native ``INTERVAL`` type is used; for others, the
value is stored as a date which is relative to the "epoch"
(Jan. 1, 1970).
Note that the ``Interval`` type does not currently provide date arithmetic
operations on platforms which do not support interval types natively. Such
operations usually require transformation of both sides of the expression
(such as, conversion of both sides into integer epoch values first) which
currently is a manual procedure (such as via
:attr:`~sqlalchemy.sql.expression.func`).
"""
impl = DateTime
epoch = dt.datetime.utcfromtimestamp(0)
def __init__(self, native=True, second_precision=None, day_precision=None):
"""Construct an Interval object.
:param native: when True, use the actual
INTERVAL type provided by the database, if
supported (currently PostgreSQL, Oracle).
Otherwise, represent the interval data as
an epoch value regardless.
:param second_precision: For native interval types
which support a "fractional seconds precision" parameter,
i.e. Oracle and PostgreSQL
:param day_precision: for native interval types which
support a "day precision" parameter, i.e. Oracle.
"""
super(Interval, self).__init__()
self.native = native
self.second_precision = second_precision
self.day_precision = day_precision
@property
def python_type(self):
return dt.timedelta
def adapt_to_emulated(self, impltype, **kw):
return _AbstractInterval.adapt(self, impltype, **kw)
def bind_processor(self, dialect):
impl_processor = self.impl.bind_processor(dialect)
epoch = self.epoch
if impl_processor:
def process(value):
if value is not None:
value = epoch + value
return impl_processor(value)
else:
def process(value):
if value is not None:
value = epoch + value
return value
return process
def result_processor(self, dialect, coltype):
impl_processor = self.impl.result_processor(dialect, coltype)
epoch = self.epoch
if impl_processor:
def process(value):
value = impl_processor(value)
if value is None:
return None
return value - epoch
else:
def process(value):
if value is None:
return None
return value - epoch
return process
class JSON(Indexable, TypeEngine):
"""Represent a SQL JSON type.
.. note:: :class:`_types.JSON`
is provided as a facade for vendor-specific
JSON types. Since it supports JSON SQL operations, it only
works on backends that have an actual JSON type, currently:
* PostgreSQL
* MySQL as of version 5.7 (MariaDB as of the 10.2 series does not)
* SQLite as of version 3.9
:class:`_types.JSON` is part of the Core in support of the growing
popularity of native JSON datatypes.
The :class:`_types.JSON` type stores arbitrary JSON format data, e.g.::
data_table = Table('data_table', metadata,
Column('id', Integer, primary_key=True),
Column('data', JSON)
)
with engine.connect() as conn:
conn.execute(
data_table.insert(),
data = {"key1": "value1", "key2": "value2"}
)
**JSON-Specific Expression Operators**
The :class:`_types.JSON`
datatype provides these additional SQL operations:
* Keyed index operations::
data_table.c.data['some key']
* Integer index operations::
data_table.c.data[3]
* Path index operations::
data_table.c.data[('key_1', 'key_2', 5, ..., 'key_n')]
* Data casters for specific JSON element types, subsequent to an index
or path operation being invoked::
data_table.c.data["some key"].as_integer()
.. versionadded:: 1.3.11
Additional operations may be available from the dialect-specific versions
of :class:`_types.JSON`, such as :class:`_postgresql.JSON` and
:class:`_postgresql.JSONB` which both offer additional PostgreSQL-specific
operations.
**Casting JSON Elements to Other Types**
Index operations, i.e. those invoked by calling upon the expression using
the Python bracket operator as in ``some_column['some key']``, return an
expression object whose type defaults to :class:`_types.JSON` by default,
so that
further JSON-oriented instructions may be called upon the result type.
However, it is likely more common that an index operation is expected
to return a specific scalar element, such as a string or integer. In
order to provide access to these elements in a backend-agnostic way,
a series of data casters are provided:
* :meth:`.JSON.Comparator.as_string` - return the element as a string
* :meth:`.JSON.Comparator.as_boolean` - return the element as a boolean
* :meth:`.JSON.Comparator.as_float` - return the element as a float
* :meth:`.JSON.Comparator.as_integer` - return the element as an integer
These data casters are implemented by supporting dialects in order to
assure that comparisons to the above types will work as expected, such as::
# integer comparison
data_table.c.data["some_integer_key"].as_integer() == 5
# boolean comparison
data_table.c.data["some_boolean"].as_boolean() == True
.. versionadded:: 1.3.11 Added type-specific casters for the basic JSON
data element types.
.. note::
The data caster functions are new in version 1.3.11, and supersede
the previous documented approaches of using CAST; for reference,
this looked like::
from sqlalchemy import cast, type_coerce
from sqlalchemy import String, JSON
cast(
data_table.c.data['some_key'], String
) == type_coerce(55, JSON)
The above case now works directly as::
data_table.c.data['some_key'].as_integer() == 5
For details on the previous comparison approach within the 1.3.x
series, see the documentation for SQLAlchemy 1.2 or the included HTML
files in the doc/ directory of the version's distribution.
**Detecting Changes in JSON columns when using the ORM**
The :class:`_types.JSON` type, when used with the SQLAlchemy ORM, does not
detect in-place mutations to the structure. In order to detect these, the
:mod:`sqlalchemy.ext.mutable` extension must be used. This extension will
allow "in-place" changes to the datastructure to produce events which
will be detected by the unit of work. See the example at :class:`.HSTORE`
for a simple example involving a dictionary.
**Support for JSON null vs. SQL NULL**
When working with NULL values, the :class:`_types.JSON`
type recommends the
use of two specific constants in order to differentiate between a column
that evaluates to SQL NULL, e.g. no value, vs. the JSON-encoded string
of ``"null"``. To insert or select against a value that is SQL NULL,
use the constant :func:`.null`::
from sqlalchemy import null
conn.execute(table.insert(), json_value=null())
To insert or select against a value that is JSON ``"null"``, use the
constant :attr:`_types.JSON.NULL`::
conn.execute(table.insert(), json_value=JSON.NULL)
The :class:`_types.JSON` type supports a flag
:paramref:`_types.JSON.none_as_null` which when set to True will result
in the Python constant ``None`` evaluating to the value of SQL
NULL, and when set to False results in the Python constant
``None`` evaluating to the value of JSON ``"null"``. The Python
value ``None`` may be used in conjunction with either
:attr:`_types.JSON.NULL` and :func:`.null` in order to indicate NULL
values, but care must be taken as to the value of the
:paramref:`_types.JSON.none_as_null` in these cases.
**Customizing the JSON Serializer**
The JSON serializer and deserializer used by :class:`_types.JSON`
defaults to
Python's ``json.dumps`` and ``json.loads`` functions; in the case of the
psycopg2 dialect, psycopg2 may be using its own custom loader function.
In order to affect the serializer / deserializer, they are currently
configurable at the :func:`_sa.create_engine` level via the
:paramref:`_sa.create_engine.json_serializer` and
:paramref:`_sa.create_engine.json_deserializer` parameters. For example,
to turn off ``ensure_ascii``::
engine = create_engine(
"sqlite://",
json_serializer=lambda obj: json.dumps(obj, ensure_ascii=False))
.. versionchanged:: 1.3.7
SQLite dialect's ``json_serializer`` and ``json_deserializer``
parameters renamed from ``_json_serializer`` and
``_json_deserializer``.
.. seealso::
:class:`_postgresql.JSON`
:class:`_postgresql.JSONB`
:class:`.mysql.JSON`
:class:`_sqlite.JSON`
.. versionadded:: 1.1
"""
__visit_name__ = "JSON"
hashable = False
NULL = util.symbol("JSON_NULL")
"""Describe the json value of NULL.
This value is used to force the JSON value of ``"null"`` to be
used as the value. A value of Python ``None`` will be recognized
either as SQL NULL or JSON ``"null"``, based on the setting
of the :paramref:`_types.JSON.none_as_null` flag; the
:attr:`_types.JSON.NULL`
constant can be used to always resolve to JSON ``"null"`` regardless
of this setting. This is in contrast to the :func:`_expression.null`
construct,
which always resolves to SQL NULL. E.g.::
from sqlalchemy import null
from sqlalchemy.dialects.postgresql import JSON
# will *always* insert SQL NULL
obj1 = MyObject(json_value=null())
# will *always* insert JSON string "null"
obj2 = MyObject(json_value=JSON.NULL)
session.add_all([obj1, obj2])
session.commit()
In order to set JSON NULL as a default value for a column, the most
transparent method is to use :func:`_expression.text`::
Table(
'my_table', metadata,
Column('json_data', JSON, default=text("'null'"))
)
While it is possible to use :attr:`_types.JSON.NULL` in this context, the
:attr:`_types.JSON.NULL` value will be returned as the value of the
column,
which in the context of the ORM or other repurposing of the default
value, may not be desirable. Using a SQL expression means the value
will be re-fetched from the database within the context of retrieving
generated defaults.
"""
def __init__(self, none_as_null=False):
"""Construct a :class:`_types.JSON` type.
:param none_as_null=False: if True, persist the value ``None`` as a
SQL NULL value, not the JSON encoding of ``null``. Note that
when this flag is False, the :func:`.null` construct can still
be used to persist a NULL value::
from sqlalchemy import null
conn.execute(table.insert(), data=null())
.. note::
:paramref:`_types.JSON.none_as_null` does **not** apply to the
values passed to :paramref:`_schema.Column.default` and
:paramref:`_schema.Column.server_default`; a value of ``None``
passed for these parameters means "no default present".
.. seealso::
:attr:`.types.JSON.NULL`
"""
self.none_as_null = none_as_null
class JSONElementType(TypeEngine):
"""Common function for index / path elements in a JSON expression."""
_integer = Integer()
_string = String()
def string_bind_processor(self, dialect):
return self._string._cached_bind_processor(dialect)
def string_literal_processor(self, dialect):
return self._string._cached_literal_processor(dialect)
def bind_processor(self, dialect):
int_processor = self._integer._cached_bind_processor(dialect)
string_processor = self.string_bind_processor(dialect)
def process(value):
if int_processor and isinstance(value, int):
value = int_processor(value)
elif string_processor and isinstance(value, util.string_types):
value = string_processor(value)
return value
return process
def literal_processor(self, dialect):
int_processor = self._integer._cached_literal_processor(dialect)
string_processor = self.string_literal_processor(dialect)
def process(value):
if int_processor and isinstance(value, int):
value = int_processor(value)
elif string_processor and isinstance(value, util.string_types):
value = string_processor(value)
return value
return process
class JSONIndexType(JSONElementType):
"""Placeholder for the datatype of a JSON index value.
This allows execution-time processing of JSON index values
for special syntaxes.
"""
class JSONPathType(JSONElementType):
"""Placeholder type for JSON path operations.
This allows execution-time processing of a path-based
index value into a specific SQL syntax.
"""
class Comparator(Indexable.Comparator, Concatenable.Comparator):
"""Define comparison operations for :class:`_types.JSON`."""
@util.dependencies("sqlalchemy.sql.default_comparator")
def _setup_getitem(self, default_comparator, index):
if not isinstance(index, util.string_types) and isinstance(
index, compat.collections_abc.Sequence
):
index = default_comparator._check_literal(
self.expr,
operators.json_path_getitem_op,
index,
bindparam_type=JSON.JSONPathType,
)
operator = operators.json_path_getitem_op
else:
index = default_comparator._check_literal(
self.expr,
operators.json_getitem_op,
index,
bindparam_type=JSON.JSONIndexType,
)
operator = operators.json_getitem_op
return operator, index, self.type
def as_boolean(self):
"""Cast an indexed value as boolean.
e.g.::
stmt = select([
mytable.c.json_column['some_data'].as_boolean()
]).where(
mytable.c.json_column['some_data'].as_boolean() == True
)
.. versionadded:: 1.3.11
"""
return self._binary_w_type(Boolean(), "as_boolean")
def as_string(self):
"""Cast an indexed value as string.
e.g.::
stmt = select([
mytable.c.json_column['some_data'].as_string()
]).where(
mytable.c.json_column['some_data'].as_string() ==
'some string'
)
.. versionadded:: 1.3.11
"""
return self._binary_w_type(String(), "as_string")
def as_integer(self):
"""Cast an indexed value as integer.
e.g.::
stmt = select([
mytable.c.json_column['some_data'].as_integer()
]).where(
mytable.c.json_column['some_data'].as_integer() == 5
)
.. versionadded:: 1.3.11
"""
return self._binary_w_type(Integer(), "as_integer")
def as_float(self):
"""Cast an indexed value as float.
e.g.::
stmt = select([
mytable.c.json_column['some_data'].as_float()
]).where(
mytable.c.json_column['some_data'].as_float() == 29.75
)
.. versionadded:: 1.3.11
"""
# note there's no Numeric or Decimal support here yet
return self._binary_w_type(Float(), "as_float")
def as_json(self):
"""Cast an indexed value as JSON.
This is the default behavior of indexed elements in any case.
Note that comparison of full JSON structures may not be
supported by all backends.
.. versionadded:: 1.3.11
"""
return self.expr
def _binary_w_type(self, typ, method_name):
if not isinstance(
self.expr, elements.BinaryExpression
) or self.expr.operator not in (
operators.json_getitem_op,
operators.json_path_getitem_op,
):
raise exc.InvalidRequestError(
"The JSON cast operator JSON.%s() only works with a JSON "
"index expression e.g. col['q'].%s()"
% (method_name, method_name)
)
expr = self.expr._clone()
expr.type = typ
return expr
comparator_factory = Comparator
@property
def python_type(self):
return dict
@property
def should_evaluate_none(self):
"""Alias of :attr:`_types.JSON.none_as_null`"""
return not self.none_as_null
@should_evaluate_none.setter
def should_evaluate_none(self, value):
self.none_as_null = not value
@util.memoized_property
def _str_impl(self):
return String(_expect_unicode=True)
def bind_processor(self, dialect):
string_process = self._str_impl.bind_processor(dialect)
json_serializer = dialect._json_serializer or json.dumps
def process(value):
if value is self.NULL:
value = None
elif isinstance(value, elements.Null) or (
value is None and self.none_as_null
):
return None
serialized = json_serializer(value)
if string_process:
serialized = string_process(serialized)
return serialized
return process
def result_processor(self, dialect, coltype):
string_process = self._str_impl.result_processor(dialect, coltype)
json_deserializer = dialect._json_deserializer or json.loads
def process(value):
if value is None:
return None
if string_process:
value = string_process(value)
return json_deserializer(value)
return process
class ARRAY(SchemaEventTarget, Indexable, Concatenable, TypeEngine):
"""Represent a SQL Array type.
.. note:: This type serves as the basis for all ARRAY operations.
However, currently **only the PostgreSQL backend has support
for SQL arrays in SQLAlchemy**. It is recommended to use the
:class:`_postgresql.ARRAY` type directly when using ARRAY types
with PostgreSQL, as it provides additional operators specific
to that backend.
:class:`_types.ARRAY` is part of the Core in support of various SQL
standard functions such as :class:`_functions.array_agg`
which explicitly involve
arrays; however, with the exception of the PostgreSQL backend and possibly
some third-party dialects, no other SQLAlchemy built-in dialect has support
for this type.
An :class:`_types.ARRAY` type is constructed given the "type"
of element::
mytable = Table("mytable", metadata,
Column("data", ARRAY(Integer))
)
The above type represents an N-dimensional array,
meaning a supporting backend such as PostgreSQL will interpret values
with any number of dimensions automatically. To produce an INSERT
construct that passes in a 1-dimensional array of integers::
connection.execute(
mytable.insert(),
data=[1,2,3]
)
The :class:`_types.ARRAY` type can be constructed given a fixed number
of dimensions::
mytable = Table("mytable", metadata,
Column("data", ARRAY(Integer, dimensions=2))
)
Sending a number of dimensions is optional, but recommended if the
datatype is to represent arrays of more than one dimension. This number
is used:
* When emitting the type declaration itself to the database, e.g.
``INTEGER[][]``
* When translating Python values to database values, and vice versa, e.g.
an ARRAY of :class:`.Unicode` objects uses this number to efficiently
access the string values inside of array structures without resorting
to per-row type inspection
* When used with the Python ``getitem`` accessor, the number of dimensions
serves to define the kind of type that the ``[]`` operator should
return, e.g. for an ARRAY of INTEGER with two dimensions::
>>> expr = table.c.column[5] # returns ARRAY(Integer, dimensions=1)
>>> expr = expr[6] # returns Integer
For 1-dimensional arrays, an :class:`_types.ARRAY` instance with no
dimension parameter will generally assume single-dimensional behaviors.
SQL expressions of type :class:`_types.ARRAY` have support for "index" and
"slice" behavior. The Python ``[]`` operator works normally here, given
integer indexes or slices. Arrays default to 1-based indexing.
The operator produces binary expression
constructs which will produce the appropriate SQL, both for
SELECT statements::
select([mytable.c.data[5], mytable.c.data[2:7]])
as well as UPDATE statements when the :meth:`_expression.Update.values`
method
is used::
mytable.update().values({
mytable.c.data[5]: 7,
mytable.c.data[2:7]: [1, 2, 3]
})
The :class:`_types.ARRAY` type also provides for the operators
:meth:`.types.ARRAY.Comparator.any` and
:meth:`.types.ARRAY.Comparator.all`. The PostgreSQL-specific version of
:class:`_types.ARRAY` also provides additional operators.
.. versionadded:: 1.1.0
.. seealso::
:class:`_postgresql.ARRAY`
"""
__visit_name__ = "ARRAY"
_is_array = True
zero_indexes = False
"""If True, Python zero-based indexes should be interpreted as one-based
on the SQL expression side."""
class Comparator(Indexable.Comparator, Concatenable.Comparator):
"""Define comparison operations for :class:`_types.ARRAY`.
More operators are available on the dialect-specific form
of this type. See :class:`.postgresql.ARRAY.Comparator`.
"""
def _setup_getitem(self, index):
if isinstance(index, slice):
return_type = self.type
if self.type.zero_indexes:
index = slice(index.start + 1, index.stop + 1, index.step)
index = Slice(
_literal_as_binds(
index.start,
name=self.expr.key,
type_=type_api.INTEGERTYPE,
),
_literal_as_binds(
index.stop,
name=self.expr.key,
type_=type_api.INTEGERTYPE,
),
_literal_as_binds(
index.step,
name=self.expr.key,
type_=type_api.INTEGERTYPE,
),
)
else:
if self.type.zero_indexes:
index += 1
if self.type.dimensions is None or self.type.dimensions == 1:
return_type = self.type.item_type
else:
adapt_kw = {"dimensions": self.type.dimensions - 1}
return_type = self.type.adapt(
self.type.__class__, **adapt_kw
)
return operators.getitem, index, return_type
def contains(self, *arg, **kw):
raise NotImplementedError(
"ARRAY.contains() not implemented for the base "
"ARRAY type; please use the dialect-specific ARRAY type"
)
@util.dependencies("sqlalchemy.sql.elements")
def any(self, elements, other, operator=None):
"""Return ``other operator ANY (array)`` clause.
Argument places are switched, because ANY requires array
expression to be on the right hand-side.
E.g.::
from sqlalchemy.sql import operators
conn.execute(
select([table.c.data]).where(
table.c.data.any(7, operator=operators.lt)
)
)
:param other: expression to be compared
:param operator: an operator object from the
:mod:`sqlalchemy.sql.operators`
package, defaults to :func:`.operators.eq`.
.. seealso::
:func:`_expression.any_`
:meth:`.types.ARRAY.Comparator.all`
"""
operator = operator if operator else operators.eq
# send plain BinaryExpression so that negate remains at None,
# leading to NOT expr for negation.
return elements.BinaryExpression(
elements._literal_as_binds(other),
elements.CollectionAggregate._create_any(self.expr),
operator,
)
@util.dependencies("sqlalchemy.sql.elements")
def all(self, elements, other, operator=None):
"""Return ``other operator ALL (array)`` clause.
Argument places are switched, because ALL requires array
expression to be on the right hand-side.
E.g.::
from sqlalchemy.sql import operators
conn.execute(
select([table.c.data]).where(
table.c.data.all(7, operator=operators.lt)
)
)
:param other: expression to be compared
:param operator: an operator object from the
:mod:`sqlalchemy.sql.operators`
package, defaults to :func:`.operators.eq`.
.. seealso::
:func:`_expression.all_`
:meth:`.types.ARRAY.Comparator.any`
"""
operator = operator if operator else operators.eq
# send plain BinaryExpression so that negate remains at None,
# leading to NOT expr for negation.
return elements.BinaryExpression(
elements._literal_as_binds(other),
elements.CollectionAggregate._create_all(self.expr),
operator,
)
comparator_factory = Comparator
def __init__(
self, item_type, as_tuple=False, dimensions=None, zero_indexes=False
):
"""Construct an :class:`_types.ARRAY`.
E.g.::
Column('myarray', ARRAY(Integer))
Arguments are:
:param item_type: The data type of items of this array. Note that
dimensionality is irrelevant here, so multi-dimensional arrays like
``INTEGER[][]``, are constructed as ``ARRAY(Integer)``, not as
``ARRAY(ARRAY(Integer))`` or such.
:param as_tuple=False: Specify whether return results
should be converted to tuples from lists. This parameter is
not generally needed as a Python list corresponds well
to a SQL array.
:param dimensions: if non-None, the ARRAY will assume a fixed
number of dimensions. This impacts how the array is declared
on the database, how it goes about interpreting Python and
result values, as well as how expression behavior in conjunction
with the "getitem" operator works. See the description at
:class:`_types.ARRAY` for additional detail.
:param zero_indexes=False: when True, index values will be converted
between Python zero-based and SQL one-based indexes, e.g.
a value of one will be added to all index values before passing
to the database.
"""
if isinstance(item_type, ARRAY):
raise ValueError(
"Do not nest ARRAY types; ARRAY(basetype) "
"handles multi-dimensional arrays of basetype"
)
if isinstance(item_type, type):
item_type = item_type()
self.item_type = item_type
self.as_tuple = as_tuple
self.dimensions = dimensions
self.zero_indexes = zero_indexes
@property
def hashable(self):
return self.as_tuple
@property
def python_type(self):
return list
def compare_values(self, x, y):
return x == y
def _set_parent(self, column, **kw):
"""Support SchemaEventTarget"""
if isinstance(self.item_type, SchemaEventTarget):
self.item_type._set_parent(column, **kw)
def _set_parent_with_dispatch(self, parent, **kw):
"""Support SchemaEventTarget"""
super(ARRAY, self)._set_parent_with_dispatch(parent)
if isinstance(self.item_type, SchemaEventTarget):
self.item_type._set_parent_with_dispatch(parent)
class REAL(Float):
"""The SQL REAL type."""
__visit_name__ = "REAL"
class FLOAT(Float):
"""The SQL FLOAT type."""
__visit_name__ = "FLOAT"
class NUMERIC(Numeric):
"""The SQL NUMERIC type."""
__visit_name__ = "NUMERIC"
class DECIMAL(Numeric):
"""The SQL DECIMAL type."""
__visit_name__ = "DECIMAL"
class INTEGER(Integer):
"""The SQL INT or INTEGER type."""
__visit_name__ = "INTEGER"
INT = INTEGER
class SMALLINT(SmallInteger):
"""The SQL SMALLINT type."""
__visit_name__ = "SMALLINT"
class BIGINT(BigInteger):
"""The SQL BIGINT type."""
__visit_name__ = "BIGINT"
class TIMESTAMP(DateTime):
"""The SQL TIMESTAMP type.
:class:`_types.TIMESTAMP` datatypes have support for timezone
storage on some backends, such as PostgreSQL and Oracle. Use the
:paramref:`~types.TIMESTAMP.timezone` argument in order to enable
"TIMESTAMP WITH TIMEZONE" for these backends.
"""
__visit_name__ = "TIMESTAMP"
def __init__(self, timezone=False):
"""Construct a new :class:`_types.TIMESTAMP`.
:param timezone: boolean. Indicates that the TIMESTAMP type should
enable timezone support, if available on the target database.
On a per-dialect basis is similar to "TIMESTAMP WITH TIMEZONE".
If the target database does not support timezones, this flag is
ignored.
"""
super(TIMESTAMP, self).__init__(timezone=timezone)
def get_dbapi_type(self, dbapi):
return dbapi.TIMESTAMP
class DATETIME(DateTime):
"""The SQL DATETIME type."""
__visit_name__ = "DATETIME"
class DATE(Date):
"""The SQL DATE type."""
__visit_name__ = "DATE"
class TIME(Time):
"""The SQL TIME type."""
__visit_name__ = "TIME"
class TEXT(Text):
"""The SQL TEXT type."""
__visit_name__ = "TEXT"
class CLOB(Text):
"""The CLOB type.
This type is found in Oracle and Informix.
"""
__visit_name__ = "CLOB"
class VARCHAR(String):
"""The SQL VARCHAR type."""
__visit_name__ = "VARCHAR"
class NVARCHAR(Unicode):
"""The SQL NVARCHAR type."""
__visit_name__ = "NVARCHAR"
class CHAR(String):
"""The SQL CHAR type."""
__visit_name__ = "CHAR"
class NCHAR(Unicode):
"""The SQL NCHAR type."""
__visit_name__ = "NCHAR"
class BLOB(LargeBinary):
"""The SQL BLOB type."""
__visit_name__ = "BLOB"
class BINARY(_Binary):
"""The SQL BINARY type."""
__visit_name__ = "BINARY"
class VARBINARY(_Binary):
"""The SQL VARBINARY type."""
__visit_name__ = "VARBINARY"
class BOOLEAN(Boolean):
"""The SQL BOOLEAN type."""
__visit_name__ = "BOOLEAN"
class NullType(TypeEngine):
"""An unknown type.
:class:`.NullType` is used as a default type for those cases where
a type cannot be determined, including:
* During table reflection, when the type of a column is not recognized
by the :class:`.Dialect`
* When constructing SQL expressions using plain Python objects of
unknown types (e.g. ``somecolumn == my_special_object``)
* When a new :class:`_schema.Column` is created,
and the given type is passed
as ``None`` or is not passed at all.
The :class:`.NullType` can be used within SQL expression invocation
without issue, it just has no behavior either at the expression
construction level or at the bind-parameter/result processing level.
:class:`.NullType` will result in a :exc:`.CompileError` if the compiler
is asked to render the type itself, such as if it is used in a
:func:`.cast` operation or within a schema creation operation such as that
invoked by :meth:`_schema.MetaData.create_all` or the
:class:`.CreateTable`
construct.
"""
__visit_name__ = "null"
_isnull = True
hashable = False
def literal_processor(self, dialect):
def process(value):
return "NULL"
return process
class Comparator(TypeEngine.Comparator):
def _adapt_expression(self, op, other_comparator):
if isinstance(
other_comparator, NullType.Comparator
) or not operators.is_commutative(op):
return op, self.expr.type
else:
return other_comparator._adapt_expression(op, self)
comparator_factory = Comparator
class MatchType(Boolean):
"""Refers to the return type of the MATCH operator.
As the :meth:`.ColumnOperators.match` is probably the most open-ended
operator in generic SQLAlchemy Core, we can't assume the return type
at SQL evaluation time, as MySQL returns a floating point, not a boolean,
and other backends might do something different. So this type
acts as a placeholder, currently subclassing :class:`.Boolean`.
The type allows dialects to inject result-processing functionality
if needed, and on MySQL will return floating-point values.
.. versionadded:: 1.0.0
"""
NULLTYPE = NullType()
BOOLEANTYPE = Boolean()
STRINGTYPE = String()
INTEGERTYPE = Integer()
MATCHTYPE = MatchType()
_type_map = {
int: Integer(),
float: Float(),
bool: BOOLEANTYPE,
decimal.Decimal: Numeric(),
dt.date: Date(),
dt.datetime: DateTime(),
dt.time: Time(),
dt.timedelta: Interval(),
util.NoneType: NULLTYPE,
}
if util.py3k:
_type_map[bytes] = LargeBinary() # noqa
_type_map[str] = Unicode()
else:
_type_map[unicode] = Unicode() # noqa
_type_map[str] = String()
_type_map_get = _type_map.get
def _resolve_value_to_type(value):
_result_type = _type_map_get(type(value), False)
if _result_type is False:
# use inspect() to detect SQLAlchemy built-in
# objects.
insp = inspection.inspect(value, False)
if (
insp is not None
and
# foil mock.Mock() and other impostors by ensuring
# the inspection target itself self-inspects
insp.__class__ in inspection._registrars
):
raise exc.ArgumentError(
"Object %r is not legal as a SQL literal value" % value
)
return NULLTYPE
else:
return _result_type
# back-assign to type_api
type_api.BOOLEANTYPE = BOOLEANTYPE
type_api.STRINGTYPE = STRINGTYPE
type_api.INTEGERTYPE = INTEGERTYPE
type_api.NULLTYPE = NULLTYPE
type_api.MATCHTYPE = MATCHTYPE
type_api.INDEXABLE = Indexable
type_api._resolve_value_to_type = _resolve_value_to_type
TypeEngine.Comparator.BOOLEANTYPE = BOOLEANTYPE
PK ! 4gE E
annotation.pynu [ # sql/annotation.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
#
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""The :class:`.Annotated` class and related routines; creates hash-equivalent
copies of SQL constructs which contain context-specific markers and
associations.
"""
from . import operators
from .. import util
class Annotated(object):
"""clones a ClauseElement and applies an 'annotations' dictionary.
Unlike regular clones, this clone also mimics __hash__() and
__cmp__() of the original element so that it takes its place
in hashed collections.
A reference to the original element is maintained, for the important
reason of keeping its hash value current. When GC'ed, the
hash value may be reused, causing conflicts.
.. note:: The rationale for Annotated producing a brand new class,
rather than placing the functionality directly within ClauseElement,
is **performance**. The __hash__() method is absent on plain
ClauseElement which leads to significantly reduced function call
overhead, as the use of sets and dictionaries against ClauseElement
objects is prevalent, but most are not "annotated".
"""
def __new__(cls, *args):
if not args:
# clone constructor
return object.__new__(cls)
else:
element, values = args
# pull appropriate subclass from registry of annotated
# classes
try:
cls = annotated_classes[element.__class__]
except KeyError:
cls = _new_annotation_type(element.__class__, cls)
return object.__new__(cls)
def __init__(self, element, values):
self.__dict__ = element.__dict__.copy()
self.__element = element
self._annotations = values
self._hash = hash(element)
def _annotate(self, values):
_values = self._annotations.copy()
_values.update(values)
return self._with_annotations(_values)
def _with_annotations(self, values):
clone = self.__class__.__new__(self.__class__)
clone.__dict__ = self.__dict__.copy()
clone._annotations = values
return clone
def _deannotate(self, values=None, clone=True):
if values is None:
return self.__element
else:
_values = self._annotations.copy()
for v in values:
_values.pop(v, None)
return self._with_annotations(_values)
def _compiler_dispatch(self, visitor, **kw):
return self.__element.__class__._compiler_dispatch(self, visitor, **kw)
@property
def _constructor(self):
return self.__element._constructor
def _clone(self):
clone = self.__element._clone()
if clone is self.__element:
# detect immutable, don't change anything
return self
else:
# update the clone with any changes that have occurred
# to this object's __dict__.
clone.__dict__.update(self.__dict__)
return self.__class__(clone, self._annotations)
def __reduce__(self):
return self.__class__, (self.__element, self._annotations)
def __hash__(self):
return self._hash
def __eq__(self, other):
if isinstance(self.__element, operators.ColumnOperators):
return self.__element.__class__.__eq__(self, other)
else:
return hash(other) == hash(self)
# hard-generate Annotated subclasses. this technique
# is used instead of on-the-fly types (i.e. type.__new__())
# so that the resulting objects are pickleable.
annotated_classes = {}
def _deep_annotate(element, annotations, exclude=None):
"""Deep copy the given ClauseElement, annotating each element
with the given annotations dictionary.
Elements within the exclude collection will be cloned but not annotated.
"""
def clone(elem):
if (
exclude
and hasattr(elem, "proxy_set")
and elem.proxy_set.intersection(exclude)
):
newelem = elem._clone()
elif annotations != elem._annotations:
newelem = elem._annotate(annotations)
else:
newelem = elem
newelem._copy_internals(clone=clone)
return newelem
if element is not None:
element = clone(element)
clone = None # remove gc cycles
return element
def _deep_deannotate(element, values=None):
"""Deep copy the given element, removing annotations."""
cloned = util.column_dict()
def clone(elem):
# if a values dict is given,
# the elem must be cloned each time it appears,
# as there may be different annotations in source
# elements that are remaining. if totally
# removing all annotations, can assume the same
# slate...
if values or elem not in cloned:
newelem = elem._deannotate(values=values, clone=True)
newelem._copy_internals(clone=clone)
if not values:
cloned[elem] = newelem
return newelem
else:
return cloned[elem]
if element is not None:
element = clone(element)
clone = None # remove gc cycles
return element
def _shallow_annotate(element, annotations):
"""Annotate the given ClauseElement and copy its internals so that
internal objects refer to the new annotated object.
Basically used to apply a "dont traverse" annotation to a
selectable, without digging throughout the whole
structure wasting time.
"""
element = element._annotate(annotations)
element._copy_internals()
return element
def _new_annotation_type(cls, base_cls):
if issubclass(cls, Annotated):
return cls
elif cls in annotated_classes:
return annotated_classes[cls]
for super_ in cls.__mro__:
# check if an Annotated subclass more specific than
# the given base_cls is already registered, such
# as AnnotatedColumnElement.
if super_ in annotated_classes:
base_cls = annotated_classes[super_]
break
annotated_classes[cls] = anno_cls = type(
"Annotated%s" % cls.__name__, (base_cls, cls), {}
)
globals()["Annotated%s" % cls.__name__] = anno_cls
return anno_cls
def _prepare_annotations(target_hierarchy, base_cls):
stack = [target_hierarchy]
while stack:
cls = stack.pop()
stack.extend(cls.__subclasses__())
_new_annotation_type(cls, base_cls)
PK ! t2 2 & __pycache__/selectable.cpython-311.pycnu [
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inspection)utilc t j | d }|)t | t j rt | |j S # t $ r3}t j t j
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SelectBaseselectr8 s r; _interpret_as_selectrD E sO ))G'5!! #" gz * * #.."" N c $ e Zd Zed ZdS )_OffsetLimitParamc | j S r> )effective_valueselfs r; _limit_offset_valuez%_OffsetLimitParam._limit_offset_valueO s ##rE N)__name__
__module__ __qualname__propertyrL rE r; rG rG N s-
$ $ X$ $ $rE rG c | dS t | d r| S t | t r| S t j | }t
|||d S )zConvert the given value to an "offset or limit" clause.
This handles incoming integers and converts to an expression; if
an expression is already given, it is passed through.
N__clause_element__T)type_unique)hasattrrS r2 r r, asintrG )r8 namerT values r; _offset_or_limit_clauserZ T sr t . / / H))+++ GY ' ' H
7## uE$GGGGrE c | dS | j }t j | S # t $ r6}t j t j d|z | Y d}~dS d}~ww xY w)zConvert the "offset or limit" clause of a select construct to an
integer.
This is only possible if the value is stored as a simple bound parameter.
Otherwise, a compilation error is raised.
Nz@This SELECT structure does not use a simple integer value for %sr/ )rL r, rW r5 r6 r* CompileError)clauseattrnamerY r: s r; _offset_or_limit_clause_asintr_ f s ~t !* z%
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s !
A!+A A!c @ t |i | | S )zReturn an :class:`_expression.Alias` object derived
from a :class:`_expression.Select`.
:param alias: the alias name
:param \*args, \**kwargs: all other arguments are delivered to the
:func:`_expression.select` function.
)Selectalias)rb argskwargss r; subqueryre ~ s% 4 "6 " " ( ( / //rE c 0 e Zd ZdZdZdZed ZdS )
Selectablez!Mark a class as being selectable.r4 Tc | S r> rQ rJ s r; r4 zSelectable.selectable s rE N)rM rN rO __doc____visit_name__
is_selectablerP r4 rQ rE r; rg rg s= ++!NM
X rE rg c V e Zd ZdZe eddd d ZddZdS ) HasPrefixesrQ exprz+:meth:`_expression.HasPrefixes.prefix_with`z*:paramref:`.HasPrefixes.prefix_with.*expr`c | dd }|r*t j dd | z | || dS )a Add one or more expressions following the statement keyword, i.e.
SELECT, INSERT, UPDATE, or DELETE. Generative.
This is used to support backend-specific prefix keywords such as those
provided by MySQL.
E.g.::
stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")
# MySQL 5.7 optimizer hints
stmt = select([table]).prefix_with(
"/*+ BKA(t1) */", dialect="mysql")
Multiple prefixes can be specified by multiple calls
to :meth:`_expression.HasPrefixes.prefix_with`.
:param \*expr: textual or :class:`_expression.ClauseElement`
construct which
will be rendered following the INSERT, UPDATE, or DELETE
keyword.
:param \**kw: A single keyword 'dialect' is accepted. This is an
optional string dialect name which will
limit rendering of this prefix to only that dialect.
dialectNUnsupported argument(s): %s,)popr* r7 join_setup_prefixesrK rn kwrp s r; prefix_withzHasPrefixes.prefix_with se B &&D))
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rE rm c V e Zd ZdZe eddd d ZddZdS ) HasSuffixesrQ rn z+:meth:`_expression.HasSuffixes.suffix_with`z*:paramref:`.HasSuffixes.suffix_with.*expr`c | dd }|r*t j dd | z | || dS )a Add one or more expressions following the statement as a whole.
This is used to support backend-specific suffix keywords on
certain constructs.
E.g.::
stmt = select([col1, col2]).cte().suffix_with(
"cycle empno set y_cycle to 1 default 0", dialect="oracle")
Multiple suffixes can be specified by multiple calls
to :meth:`_expression.HasSuffixes.suffix_with`.
:param \*expr: textual or :class:`_expression.ClauseElement`
construct which
will be rendered following the target clause.
:param \**kw: A single keyword 'dialect' is accepted. This is an
optional string dialect name which will
limit rendering of this suffix to only that dialect.
rp Nrq rr )rs r* r7 rt _setup_suffixesrv s r; suffix_withzHasSuffixes.suffix_with sd 8 &&D))
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T7+++++rE Nc X | j t fd|D z | _ d S )Nc 6 g | ]}t |d fS r{ r r} s r; r z/HasSuffixes._setup_suffixes.. r rE ) _suffixesr )rK suffixesrp s `r; r zHasSuffixes._setup_suffixes r rE r> )rM rN rO r r
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FromClauseaE Represent an element that can be used within the ``FROM``
clause of a ``SELECT`` statement.
The most common forms of :class:`_expression.FromClause` are the
:class:`_schema.Table` and the :func:`_expression.select` constructs. Key
features common to all :class:`_expression.FromClause` objects include:
* a :attr:`.c` collection, which provides per-name access to a collection
of :class:`_expression.ColumnElement` objects.
* a :attr:`.primary_key` attribute, which is a collection of all those
:class:`_expression.ColumnElement`
objects that indicate the ``primary_key`` flag.
* Methods to generate various derivations of a "from" clause, including
:meth:`_expression.FromClause.alias`,
:meth:`_expression.FromClause.join`,
:meth:`_expression.FromClause.select`.
fromclauseFNc |S r> rQ )rK effective_schemamap_s r; _translate_schemaz FromClause._translate_schema' s rE _columnsz1.1zThe :meth:`.FromClause.count` method is deprecated, and will be removed in a future release. Please use the :class:`_functions.count` function available from the :attr:`.func` namespace.messagesqlalchemy.sql.functionsc | j rt | j d }nt | j d }t |j | d g|fd| gi|S )zReturn a SELECT COUNT generated against this
:class:`_expression.FromClause`.
.. seealso::
:class:`_functions.count`
r
tbl_row_countfrom_obj) primary_keylistcolumnsra funccountlabel)rK functions whereclauseparamscols r; r zFromClause.count, s $ (t'((+CCt|$$Q'C
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rE c t | g|fi |S )zReturn a SELECT of this :class:`_expression.FromClause`.
.. seealso::
:func:`_expression.select` - general purpose
method which allows for arbitrary column lists.
ra rK r r s r; rB zFromClause.selectI s tfk44V444rE c ( t | |||| S )a Return a :class:`_expression.Join` from this
:class:`_expression.FromClause` to another
:class:`_expression.FromClause`.
E.g.::
from sqlalchemy import join
j = user_table.join(address_table,
user_table.c.id == address_table.c.user_id)
stmt = select([user_table]).select_from(j)
would emit SQL along the lines of::
SELECT user.id, user.name FROM user
JOIN address ON user.id = address.user_id
:param right: the right side of the join; this is any
:class:`_expression.FromClause` object such as a
:class:`_schema.Table` object, and
may also be a selectable-compatible object such as an ORM-mapped
class.
:param onclause: a SQL expression representing the ON clause of the
join. If left at ``None``, :meth:`_expression.FromClause.join`
will attempt to
join the two tables based on a foreign key relationship.
:param isouter: if True, render a LEFT OUTER JOIN, instead of JOIN.
:param full: if True, render a FULL OUTER JOIN, instead of LEFT OUTER
JOIN. Implies :paramref:`.FromClause.join.isouter`.
.. versionadded:: 1.1
.. seealso::
:func:`_expression.join` - standalone function
:class:`_expression.Join` - the type of object produced
Join)rK rightonclauseisouterfulls r; rt zFromClause.joinU s X D%7D999rE c ( t | ||d| S )a Return a :class:`_expression.Join` from this
:class:`_expression.FromClause`
to another :class:`FromClause`, with the "isouter" flag set to
True.
E.g.::
from sqlalchemy import outerjoin
j = user_table.outerjoin(address_table,
user_table.c.id == address_table.c.user_id)
The above is equivalent to::
j = user_table.join(
address_table,
user_table.c.id == address_table.c.user_id,
isouter=True)
:param right: the right side of the join; this is any
:class:`_expression.FromClause` object such as a
:class:`_schema.Table` object, and
may also be a selectable-compatible object such as an ORM-mapped
class.
:param onclause: a SQL expression representing the ON clause of the
join. If left at ``None``, :meth:`_expression.FromClause.join`
will attempt to
join the two tables based on a foreign key relationship.
:param full: if True, render a FULL OUTER JOIN, instead of
LEFT OUTER JOIN.
.. versionadded:: 1.1
.. seealso::
:meth:`_expression.FromClause.join`
:class:`_expression.Join`
Tr )rK r r r s r; outerjoinzFromClause.outerjoin s X D%4666rE c 8 t | | S )as Return an alias of this :class:`_expression.FromClause`.
E.g.::
a2 = some_table.alias('a2')
The above code creates an :class:`_expression.Alias`
object which can be used
as a FROM clause in any SELECT statement.
.. seealso::
:ref:`core_tutorial_aliases`
:func:`_expression.alias`
)r?
_constructrK rX flats r; rb zFromClause.alias s & d+++rE c 8 t | | S )aM Return a LATERAL alias of this :class:`_expression.FromClause`.
The return value is the :class:`_expression.Lateral` construct also
provided by the top-level :func:`_expression.lateral` function.
.. versionadded:: 1.1
.. seealso::
:ref:`lateral_selects` - overview of usage.
)Lateralr rK rX s r; lateralzFromClause.lateral s !!$---rE c < t | ||| S )av Return a TABLESAMPLE alias of this :class:`_expression.FromClause`.
The return value is the :class:`_expression.TableSample`
construct also
provided by the top-level :func:`_expression.tablesample` function.
.. versionadded:: 1.1
.. seealso::
:func:`_expression.tablesample` - usage guidelines and parameters
) TableSampler )rK samplingrX seeds r; tablesamplezFromClause.tablesample s %%dHdDAAArE c || j v S )zReturn ``True`` if this :class:`_expression.FromClause` is
'derived' from the given ``FromClause``.
An example would be an Alias of a Table is derived from that Table.
) _cloned_setrK r s r; is_derived_fromzFromClause.is_derived_from s T ---rE c @ | j |j S )zReturn ``True`` if this :class:`_expression.FromClause` and
the other represent the same lexical identity.
This tests if either one is a copy of the other, or
if they are the same via annotation identity.
)r intersectionrK others r; _is_lexical_equivalentz!FromClause._is_lexical_equivalent s ,,U->???rE sqlalchemy.sql.utilc R | | | S )zReplace all occurrences of FromClause 'old' with the given Alias
object, returning a copy of this :class:`_expression.FromClause`.
)
ClauseAdaptertraverse)rK sqlutiloldrb s r; replace_selectablez FromClause.replace_selectable s& $$U++44T:::rE c | |d }|,||v r(|| D ] }| |d }|r|c S |S )zzReturn corresponding_column for the given column, or if None
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'''FF ;3+--$S)
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}}|S )aX Given a :class:`_expression.ColumnElement`, return the exported
:class:`_expression.ColumnElement` object from this
:class:`expression.Selectable`
which corresponds to that original
:class:`~sqlalchemy.schema.Column` via a common ancestor
column.
:param column: the target :class:`_expression.ColumnElement`
to be matched
:param require_embedded: only return corresponding columns for
the given :class:`_expression.ColumnElement`, if the given
:class:`_expression.ColumnElement`
is actually present within a sub-element
of this :class:`_expression.FromClause`.
Normally the column will match if
it merely shares a common ancestor with one of the exported
columns of this :class:`_expression.FromClause`.
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rX z object)getattr __class__rM rJ s r; descriptionzFromClause.descriptioni s tVT^% NFFNFr F),rM rN rO ri rj named_with_column _hide_froms_is_join
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:meth:`_expression.FromClause.join` method
of any :class:`_expression.FromClause` (e.g. such as
:class:`_schema.Table`).
.. seealso::
:func:`_expression.join`
:meth:`_expression.FromClause.join`
rt TNFc t | | _ t | | _ |&| | j | j | _ n|| _ || _ || _ dS )zConstruct a new :class:`_expression.Join`.
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function or the :meth:`_expression.FromClause.join` method of any
:class:`_expression.FromClause` object.
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self_groupr _match_primariesr r r )rK r$ r r r r s r; __init__z
Join.__init__ sj 't,, '..99;;
1 1$)TZ H HDMM $DM rE c " | |||d| S )a Return an ``OUTER JOIN`` clause element.
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:meth:`_expression.FromClause.outerjoin` method on any
:class:`_expression.FromClause`.
:param left: The left side of the join.
:param right: The right side of the join.
:param onclause: Optional criterion for the ``ON`` clause, is
derived from foreign key relationships established between
left and right otherwise.
To chain joins together, use the :meth:`_expression.FromClause.join`
or
:meth:`_expression.FromClause.outerjoin` methods on the resulting
:class:`_expression.Join` object.
Tr r rQ )clsr$ r r r s r; _create_outerjoinzJoin._create_outerjoin s 0 s4$TBBBBrE c | ||||| S )a8 Produce a :class:`_expression.Join` object, given two
:class:`_expression.FromClause`
expressions.
E.g.::
j = join(user_table, address_table,
user_table.c.id == address_table.c.user_id)
stmt = select([user_table]).select_from(j)
would emit SQL along the lines of::
SELECT user.id, user.name FROM user
JOIN address ON user.id = address.user_id
Similar functionality is available given any
:class:`_expression.FromClause` object (e.g. such as a
:class:`_schema.Table`) using
the :meth:`_expression.FromClause.join` method.
:param left: The left side of the join.
:param right: the right side of the join; this is any
:class:`_expression.FromClause` object such as a
:class:`_schema.Table` object, and
may also be a selectable-compatible object such as an ORM-mapped
class.
:param onclause: a SQL expression representing the ON clause of the
join. If left at ``None``, :meth:`_expression.FromClause.join`
will attempt to
join the two tables based on a foreign key relationship.
:param isouter: if True, render a LEFT OUTER JOIN, instead of JOIN.
:param full: if True, render a FULL OUTER JOIN, instead of JOIN.
.. versionadded:: 1.1
.. seealso::
:meth:`_expression.FromClause.join` - method form,
based on a given left side.
:class:`_expression.Join` - the type of object produced.
rQ )r* r$ r r r r s r; _create_joinzJoin._create_join s h s4'4888rE c d| j j t | j | j j t | j fz S )Nz Join object on %s(%d) and %s(%d))r$ r idr rJ s r; r zJoin.descriptionT s: 1 I ! tyMM J " tzNN 5
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rE c * | j | j | j fS r> )r$ r r rK rd s r; get_childrenzJoin.get_children s y$*dm33rE c p t |t r|j }nd }| ||| S )N)a_subset)r2 r r _join_condition)rK r$ r
left_rights r; r& zJoin._match_primaries s= dD ! ! JJ J##D%*#EEErE )0.9zThe :paramref:`.join_condition.ignore_nonexistent_tables` parameter is deprecated and will be removed in a future release. Tables outside of the two tables being handled are no longer considered.)ignore_nonexistent_tablesc | |||| }t | dk r| |||| t | dk rAt |t rd}nd}t j d|j d|j d| d t | d D }t | dk r|d S t | S ) a Create a join condition between two tables or selectables.
e.g.::
join_condition(tablea, tableb)
would produce an expression along the lines of::
tablea.c.id==tableb.c.tablea_id
The join is determined based on the foreign key relationships
between the two selectables. If there are multiple ways
to join, or no way to join, an error is raised.
:param ignore_nonexistent_tables: unused - tables outside of the
two tables being handled are not considered.
:param a_subset: An optional expression that is a sub-component
of ``a``. An attempt will be made to join to just this sub-component
first before looking at the full ``a`` construct, and if found
will be successful even if there are other ways to join to ``a``.
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providing a "natural join".
r r zI Perhaps you meant to convert the right side to a subquery using alias()? z2Can't find any foreign key relationships between '' and 'z'.c g | ] \ }}||k S rQ rQ )r~ xys r; r z(Join._join_condition.. s CCCTQaCCCrE ) _joincond_scan_left_rightr _joincond_trim_constraintsr2 r3 r* NoForeignKeysErrorr r valuesr! ) r* abrT rP consider_as_foreign_keys constraintshintcrits r; rQ zJoin._join_condition s V 33
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A B"/)B B"9DE )E Ec |rDt | D ]4}t d |j D t | k r||= 5t | dk r]t d | D }t | dk r t | d }||| i}t | dk r%t j d|j d|j d d S )Nc 3 $ K | ] }|j V d S r> )rk r~ fs r; r< z2Join._joincond_trim_constraints..* s$ 88Aqx888888rE r c 3 4 K | ]}t | V d S r> )r )r~ rd s r; r< z2Join._joincond_trim_constraints..2 s( FFtFFFFFFrE r z Can't determine join between 'rW z'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly.)r r elementsr r^ r* AmbiguousForeignKeysErrorr )r* r_ r` rb ra constdeduper s r; r\ z Join._joincond_trim_constraints! s $ + k**
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:class:`_expression.Join`.
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object
``j``, is::
from sqlalchemy import select
j = select([j.left, j.right], **kw).\
where(whereclause).\
select_from(j)
:param whereclause: the WHERE criterion that will be sent to
the :func:`select()` function
:param \**kwargs: all other kwargs are sent to the
underlying :func:`select()` function.
r )r$ r ra )rK r rd collists r; rB z Join.select@ s1 ( 9dj)g{FFdVFvFFFrE c 2 | j j p | j j S r> )r$ bindr rJ s r; r z Join.bindX s y~0 0rE c |r|
J d | j d | j d }}| | | | }| || | j | j | j S |
dd | S )a Return an alias of this :class:`_expression.Join`.
The default behavior here is to first produce a SELECT
construct from this :class:`_expression.Join`, then to produce an
:class:`_expression.Alias` from that. So given a join of the form::
j = table_a.join(table_b, table_a.c.id == table_b.c.a_id)
The JOIN by itself would look like::
table_a JOIN table_b ON table_a.id = table_b.a_id
Whereas the alias of the above, ``j.alias()``, would in a
SELECT context look like::
(SELECT table_a.id AS table_a_id, table_b.id AS table_b_id,
table_b.a_id AS table_b_a_id
FROM table_a
JOIN table_b ON table_a.id = table_b.a_id) AS anon_1
The equivalent long-hand form, given a :class:`_expression.Join`
object
``j``, is::
from sqlalchemy import select, alias
j = alias(
select([j.left, j.right]).\
select_from(j).\
with_labels(True).\
correlate(False),
name=name
)
The selectable produced by :meth:`_expression.Join.alias`
features the same
columns as that of the two individual selectables presented under
a single name - the individual columns are "auto-labeled", meaning
the ``.c.`` collection of the resulting :class:`_expression.Alias`
represents
the names of the individual columns using a
``_`` scheme::
j.c.table_a_id
j.c.table_b_a_id
:meth:`_expression.Join.alias` also features an alternate
option for aliasing joins which produces no enclosing SELECT and
does not normally apply labels to the column names. The
``flat=True`` option will call :meth:`_expression.FromClause.alias`
against the left and right sides individually.
Using this option, no new ``SELECT`` is produced;
we instead, from a construct as below::
j = table_a.join(table_b, table_a.c.id == table_b.c.a_id)
j = j.alias(flat=True)
we get a result like this::
table_a AS table_a_1 JOIN table_b AS table_b_1 ON
table_a_1.id = table_b_1.a_id
The ``flat=True`` argument is also propagated to the contained
selectables, so that a composite join such as::
j = table_a.join(
table_b.join(table_c,
table_b.c.id == table_c.c.b_id),
table_b.c.a_id == table_a.c.id
).alias(flat=True)
Will produce an expression like::
table_a AS table_a_1 JOIN (
table_b AS table_b_1 JOIN table_c AS table_c_1
ON table_b_1.id = table_c_1.b_id
) ON table_a_1.id = table_b_1.a_id
The standalone :func:`_expression.alias` function as well as the
base :meth:`_expression.FromClause.alias`
method also support the ``flat=True``
argument as a no-op, so that the argument can be passed to the
``alias()`` method of any selectable.
.. versionadded:: 0.9.0 Added the ``flat=True`` option to create
"aliases" of joins without enclosing inside of a SELECT
subquery.
:param name: name given to the alias.
:param flat: if True, produce an alias of the left and right
sides of this :class:`_expression.Join` and return the join of those
two selectables. This produces join expression that does not
include an enclosing SELECT.
.. versionadded:: 0.9.0
.. seealso::
:ref:`core_tutorial_aliases`
:func:`_expression.alias`
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Represents an alias, as typically applied to any table or
sub-select within a SQL statement using the ``AS`` keyword (or
without the keyword on certain databases such as Oracle).
This object is constructed from the :func:`_expression.alias` module
level function as well as the :meth:`_expression.FromClause.alias`
method available
on all :class:`_expression.FromClause` subclasses.
rb Tc t d| j j d| j j d| j j d )NzThe zC class is not intended to be constructed directly. Please use the z () standalone function or the z8() method available from appropriate selectable objects.)NotImplementedErrorr rM lower)rK argrw s r; r' zAlias.__init__ s` !! ''''--////'--////
rE c J | | } |j |i | |S r> )__new___init)r* r rw objs r; r zAlias._construct s/ kk# 3 "
rE NFc J t | || S )a Return an :class:`_expression.Alias` object.
An :class:`_expression.Alias` represents any
:class:`_expression.FromClause`
with an alternate name assigned within SQL, typically using the ``AS``
clause when generated, e.g. ``SELECT * FROM table AS aliasname``.
Similar functionality is available via the
:meth:`_expression.FromClause.alias`
method available on all :class:`_expression.FromClause` subclasses.
In terms of
a SELECT object as generated from the :func:`_expression.select`
function, the :meth:`_expression.SelectBase.alias` method returns an
:class:`_expression.Alias` or similar object which represents a named,
parenthesized subquery.
When an :class:`_expression.Alias` is created from a
:class:`_schema.Table` object,
this has the effect of the table being rendered
as ``tablename AS aliasname`` in a SELECT statement.
For :func:`_expression.select` objects, the effect is that of
creating a named subquery, i.e. ``(select ...) AS aliasname``.
The ``name`` parameter is optional, and provides the name
to use in the rendered SQL. If blank, an "anonymous" name
will be deterministically generated at compile time.
Deterministic means the name is guaranteed to be unique against
other constructs used in the same statement, and will also be the
same name for each successive compilation of the same statement
object.
:param selectable: any :class:`_expression.FromClause` subclass,
such as a table, select statement, etc.
:param name: string name to be assigned as the alias.
If ``None``, a name will be deterministically generated
at compile time.
:param flat: Will be passed through to if the given selectable
is an instance of :class:`_expression.Join` - see
:meth:`_expression.Join.alias`
for details.
.. versionadded:: 0.9.0
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8 8 8
" " " %+ ' ' ' ' X ! ! X! ! ! ! !rE r? c 2 e Zd ZdZdZdZedd ZdS )r a Represent a LATERAL subquery.
This object is constructed from the :func:`_expression.lateral` module
level function as well as the :meth:`_expression.FromClause.lateral`
method available
on all :class:`_expression.FromClause` subclasses.
While LATERAL is part of the SQL standard, currently only more recent
PostgreSQL versions provide support for this keyword.
.. versionadded:: 1.1
.. seealso::
:ref:`lateral_selects` - overview of usage.
r TNc H t | | S )a Return a :class:`_expression.Lateral` object.
:class:`_expression.Lateral` is an :class:`_expression.Alias`
subclass that represents
a subquery with the LATERAL keyword applied to it.
The special behavior of a LATERAL subquery is that it appears in the
FROM clause of an enclosing SELECT, but may correlate to other
FROM clauses of that SELECT. It is a special case of subquery
only supported by a small number of backends, currently more recent
PostgreSQL versions.
.. versionadded:: 1.1
.. seealso::
:ref:`lateral_selects` - overview of usage.
rr )r< r )r* r4 rX s r; r zLateral._factory s# * "*--5545@@@rE r> )rM rN rO ri rj r r r rQ rE r; r r sN $ NKA A A [A A ArE r c r e Zd ZdZdZedd Zd fd Z ej d d Z
xZ S ) r ad Represent a TABLESAMPLE clause.
This object is constructed from the :func:`_expression.tablesample` module
level function as well as the :meth:`_expression.FromClause.tablesample`
method
available on all :class:`_expression.FromClause` subclasses.
.. versionadded:: 1.1
.. seealso::
:func:`_expression.tablesample`
r Nc L t | ||| S )a Return a :class:`_expression.TableSample` object.
:class:`_expression.TableSample` is an :class:`_expression.Alias`
subclass that represents
a table with the TABLESAMPLE clause applied to it.
:func:`_expression.tablesample`
is also available from the :class:`_expression.FromClause`
class via the
:meth:`_expression.FromClause.tablesample` method.
The TABLESAMPLE clause allows selecting a randomly selected approximate
percentage of rows from a table. It supports multiple sampling methods,
most commonly BERNOULLI and SYSTEM.
e.g.::
from sqlalchemy import func
selectable = people.tablesample(
func.bernoulli(1),
name='alias',
seed=func.random())
stmt = select([selectable.c.people_id])
Assuming ``people`` with a column ``people_id``, the above
statement would render as::
SELECT alias.people_id FROM
people AS alias TABLESAMPLE bernoulli(:bernoulli_1)
REPEATABLE (random())
.. versionadded:: 1.1
:param sampling: a ``float`` percentage between 0 and 100 or
:class:`_functions.Function`.
:param name: optional alias name
:param seed: any real-valued SQL expression. When specified, the
REPEATABLE sub-clause is also rendered.
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Zd Zd Z xZS )CTEzRepresent a Common Table Expression.
The :class:`_expression.CTE` object is obtained using the
:meth:`_expression.SelectBase.cte` method from any selectable.
See that method for complete examples.
cteNFc J t | || S )zReturn a new :class:`_expression.CTE`,
or Common Table Expression instance.
Please see :meth:`_expression.HasCTE.cte` for detail on CTE usage.
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&rE c j t | j || j | | j | j S )a1 Return an :class:`_expression.Alias` of this
:class:`_expression.CTE`.
This method is a CTE-specific specialization of the
:meth:`_expression.FromClause.alias` method.
.. seealso::
:ref:`core_tutorial_aliases`
:func:`_expression.alias`
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.. versionadded:: 1.1
NFc < t | || S )a Return a new :class:`_expression.CTE`,
or Common Table Expression instance.
Common table expressions are a SQL standard whereby SELECT
statements can draw upon secondary statements specified along
with the primary statement, using a clause called "WITH".
Special semantics regarding UNION can also be employed to
allow "recursive" queries, where a SELECT statement can draw
upon the set of rows that have previously been selected.
CTEs can also be applied to DML constructs UPDATE, INSERT
and DELETE on some databases, both as a source of CTE rows
when combined with RETURNING, as well as a consumer of
CTE rows.
.. versionchanged:: 1.1 Added support for UPDATE/INSERT/DELETE as
CTE, CTEs added to UPDATE/INSERT/DELETE.
SQLAlchemy detects :class:`_expression.CTE` objects, which are treated
similarly to :class:`_expression.Alias` objects, as special elements
to be delivered to the FROM clause of the statement as well
as to a WITH clause at the top of the statement.
For special prefixes such as PostgreSQL "MATERIALIZED" and
"NOT MATERIALIZED", the :meth:`_expression.CTE.prefix_with`
method may be
used to establish these.
.. versionchanged:: 1.3.13 Added support for prefixes.
In particular - MATERIALIZED and NOT MATERIALIZED.
:param name: name given to the common table expression. Like
:meth:`_expression.FromClause.alias`, the name can be left as
``None`` in which case an anonymous symbol will be used at query
compile time.
:param recursive: if ``True``, will render ``WITH RECURSIVE``.
A recursive common table expression is intended to be used in
conjunction with UNION ALL in order to derive rows
from those already selected.
The following examples include two from PostgreSQL's documentation at
http://www.postgresql.org/docs/current/static/queries-with.html,
as well as additional examples.
Example 1, non recursive::
from sqlalchemy import (Table, Column, String, Integer,
MetaData, select, func)
metadata = MetaData()
orders = Table('orders', metadata,
Column('region', String),
Column('amount', Integer),
Column('product', String),
Column('quantity', Integer)
)
regional_sales = select([
orders.c.region,
func.sum(orders.c.amount).label('total_sales')
]).group_by(orders.c.region).cte("regional_sales")
top_regions = select([regional_sales.c.region]).\
where(
regional_sales.c.total_sales >
select([
func.sum(regional_sales.c.total_sales)/10
])
).cte("top_regions")
statement = select([
orders.c.region,
orders.c.product,
func.sum(orders.c.quantity).label("product_units"),
func.sum(orders.c.amount).label("product_sales")
]).where(orders.c.region.in_(
select([top_regions.c.region])
)).group_by(orders.c.region, orders.c.product)
result = conn.execute(statement).fetchall()
Example 2, WITH RECURSIVE::
from sqlalchemy import (Table, Column, String, Integer,
MetaData, select, func)
metadata = MetaData()
parts = Table('parts', metadata,
Column('part', String),
Column('sub_part', String),
Column('quantity', Integer),
)
included_parts = select([
parts.c.sub_part,
parts.c.part,
parts.c.quantity]).\
where(parts.c.part=='our part').\
cte(recursive=True)
incl_alias = included_parts.alias()
parts_alias = parts.alias()
included_parts = included_parts.union_all(
select([
parts_alias.c.sub_part,
parts_alias.c.part,
parts_alias.c.quantity
]).
where(parts_alias.c.part==incl_alias.c.sub_part)
)
statement = select([
included_parts.c.sub_part,
func.sum(included_parts.c.quantity).
label('total_quantity')
]).\
group_by(included_parts.c.sub_part)
result = conn.execute(statement).fetchall()
Example 3, an upsert using UPDATE and INSERT with CTEs::
from datetime import date
from sqlalchemy import (MetaData, Table, Column, Integer,
Date, select, literal, and_, exists)
metadata = MetaData()
visitors = Table('visitors', metadata,
Column('product_id', Integer, primary_key=True),
Column('date', Date, primary_key=True),
Column('count', Integer),
)
# add 5 visitors for the product_id == 1
product_id = 1
day = date.today()
count = 5
update_cte = (
visitors.update()
.where(and_(visitors.c.product_id == product_id,
visitors.c.date == day))
.values(count=visitors.c.count + count)
.returning(literal(1))
.cte('update_cte')
)
upsert = visitors.insert().from_select(
[visitors.c.product_id, visitors.c.date, visitors.c.count],
select([literal(product_id), literal(day), literal(count)])
.where(~exists(update_cte.select()))
)
connection.execute(upsert)
.. seealso::
:meth:`.orm.query.Query.cte` - ORM version of
:meth:`_expression.HasCTE.cte`.
r )r r )rK rX r s r; r z
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$ $ X$ ( ( X( ) ) X)5 5 56 6 6 ( ( X( %+ 1 1 1 1 * * X*+ + +) ) )( ( ( ( (rE r3 c e Zd ZdZdZdZdZ dZ fdZd Z e
j d Z d Z
dd
Z e
j d dd Z e
j d dd
Z e
j d dd Zed Z xZS )r a- Represents a minimal "table" construct.
This is a lightweight table object that has only a name, a
collection of columns, which are typically produced
by the :func:`_expression.column` function, and a schema::
from sqlalchemy import table, column
user = table("user",
column("id"),
column("name"),
column("description"),
)
The :class:`_expression.TableClause` construct serves as the base for
the more commonly used :class:`_schema.Table` object, providing
the usual set of :class:`_expression.FromClause` services including
the ``.c.`` collection and statement generation methods.
It does **not** provide all the additional schema-level services
of :class:`_schema.Table`, including constraints, references to other
tables, or support for :class:`_schema.MetaData`-level services.
It's useful
on its own as an ad-hoc construct used to generate quick SQL
statements when a more fully fledged :class:`_schema.Table`
is not on hand.
tableTFNc t t | |x| _ | _ t | _ t | _ t | _
|D ]}| | | dd }||| _
|r$t j dt! | z dS )a Produce a new :class:`_expression.TableClause`.
The object returned is an instance of
:class:`_expression.TableClause`, which
represents the "syntactical" portion of the schema-level
:class:`_schema.Table` object.
It may be used to construct lightweight table constructs.
.. versionchanged:: 1.0.0 :func:`_expression.table` can now
be imported from the plain ``sqlalchemy`` namespace like any
other SQL element.
:param name: Name of the table.
:param columns: A collection of :func:`_expression.column` constructs.
:param schema: The schema name for this table.
.. versionadded:: 1.3.18 :func:`_expression.table` can now
accept a ``schema`` argument.
r Nrq )r r r' rX fullnamer r r r r r
append_columnrs r r* r7 r )rK rX r rw r r r s r; r' zTableClause.__init__ s 0 k4 ))+++$(( DM(**
$;; EE " "A q ! ! ! !$'' DK
N#$ADHH$LMM M N NrE c d S r> rQ rJ s r; r z TableClause._init_collections r rE c ^ t j r| j S | j dd S r r rJ s r; r zTableClause.description r rE c
|j }|2|| ur.t j d|j dt |d| || j |j < | |_ d S )Nzcolumn object 'z ' already assigned to table r )r r* r7 r r r )rK r existings r; r zTableClause.append_column sl 7 HD$8$8##555'(M8DDDF
!
ae rE c , |rd | j D S g S )Nc g | ]}|S rQ rQ r9 s r; r z,TableClause.get_children.. s &&&!A&&&rE )r rK r rd s r; rN zTableClause.get_children s% &&tv&&& &IrE r c $ |j | f||d|S )zGenerate an :func:`_expression.insert` construct against this
:class:`_expression.TableClause`.
E.g.::
table.insert().values(name='foo')
See :func:`_expression.insert` for argument and usage information.
)r^ inline)Insert)rK r r^ r rd s r; insertzTableClause.insert s% sz$GvfGGGGGrE c & |j | f|||d|S )a Generate an :func:`_expression.update` construct against this
:class:`_expression.TableClause`.
E.g.::
table.update().where(table.c.id==7).values(name='foo')
See :func:`_expression.update` for argument and usage information.
)r r^ r )Update)rK r r r^ r rd s r; rC zTableClause.update s: sz
#
rE c |j | |fi |S )zGenerate a :func:`_expression.delete` construct against this
:class:`_expression.TableClause`.
E.g.::
table.delete().where(table.c.id==7)
See :func:`_expression.delete` for argument and usage information.
)Delete)rK r r rd s r; deletezTableClause.delete s sz$ 66v666rE c | gS r> rQ rJ s r; r zTableClause._from_objects r rE r r )NNFr> )rM rN rO ri rj r implicit_returning_autoincrement_columnr' r r, memoized_propertyr r rN r r rC r rP r r r s @r; r r f sn : N = !>$N $N $N $N $NL
A A A T+,, H H H -, H T+,,9>
-,
, T+,, 7 7 7 -, 7 X rE r c b e Zd Zed Zed Zd Zd Ze fdZ
d dZ dS )
ForUpdateArgc |dv rdS dx}}|dk rd}n/|dk rd}n&|dk rdx}}n|durt j d|z t || S )
a Parse the for_update argument of :func:`_expression.select`.
:param mode: Defines the lockmode to use.
``None`` - translates to no lockmode
``'update'`` - translates to ``FOR UPDATE``
(standard SQL, supported by most dialects)
``'nowait'`` - translates to ``FOR UPDATE NOWAIT``
(supported by Oracle, PostgreSQL 8.1 upwards)
``'read'`` - translates to ``LOCK IN SHARE MODE`` (for MySQL),
and ``FOR SHARE`` (for PostgreSQL)
``'read_nowait'`` - translates to ``FOR SHARE NOWAIT``
(supported by PostgreSQL). ``FOR SHARE`` and
``FOR SHARE NOWAIT`` (PostgreSQL).
r NFnowaitTread read_nowaitz Unknown for_update argument: %rr$ r# )r* r7 r! )rK r r# r$ s r; parse_legacy_selectz ForUpdateArg.parse_legacy_select s , - 4 (??FF
F]]DD
M
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! D66
__#$E$KLL Lf5555rE c X | j r | j sdS | j r | j rdS | j rdS dS )Nr$ r% r# Tr& rJ s r; legacy_for_update_valuez$ForUpdateArg.legacy_for_update_value1 sF 9 T[ 6
Y 4; =
[ 84rE c t |t oM|j | j k o=|j | j k o-|j | j k o |j | j k o
|j | j u S r> )r2 r! r# r$ skip_locked key_shareofr s r; __eq__zForUpdateArg.__eq__< sq ul + +
$ +
$
di'
$ !T%55
$ 4>1
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DG#
rE c t | S r> )r/ rJ s r; __hash__zForUpdateArg.__hash__F s
$xxrE c N | j fd| j D | _ d S d S )Nc " g | ] } |fi S rQ rQ )r~ r rJ rw s r; r z0ForUpdateArg._copy_internals..K s+ ;;;CuuS''B'';;;rE )r- rI s ``r; rK z ForUpdateArg._copy_internalsI s8 7 ;;;;;47;;;DGGG rE FNc || _ || _ || _ || _ |%d t j | D | _ dS d| _ dS )z{Represents arguments specified to
:meth:`_expression.Select.for_update`.
.. versionadded:: 0.9.0
Nc , g | ]}t | S rQ r )r~ r s r; r z)ForUpdateArg.__init__..a s. 7;,T22 rE )r# r$ r+ r, r, to_listr- rK r# r$ r- r+ r, s r; r' zForUpdateArg.__init__M sa &"
> ?C|B?O?O DGGG DGGGrE FFNFF) rM rN rO r r' rP r) r. r0 r rK r' rQ rE r; r! r! s "6 "6 ["6H X
%+ < < < <
rE r! c e Zd ZdZd Zd Ze ej dd d Z d Z
e d Z d
S ) rA zBase class for SELECT statements.
This includes :class:`_expression.Select`,
:class:`_selectable.CompoundSelect` and
:class:`.TextAsFrom`.
c t | S )aL Return a 'scalar' representation of this selectable, which can be
used as a column expression.
Typically, a select statement which has only one column in its columns
clause is eligible to be used as a scalar expression.
The returned object is an instance of
:class:`ScalarSelect`.
) ScalarSelectrJ s r; r zSelectBase.as_scalars s D!!!rE c P | | S )zReturn a 'scalar' representation of this selectable, embedded as a
subquery with a label.
.. seealso::
:meth:`_expression.SelectBase.as_scalar`.
)r r r s r; r zSelectBase.label s" ~~ %%d+++rE 0.6zThe :meth:`.SelectBase.autocommit` method is deprecated, and will be removed in a future release. Please use the the :paramref:`.Connection.execution_options.autocommit` parameter in conjunction with the :meth:`.Executable.execution_options` method.r c H | j ddi | _ dS )zQReturn a new selectable with the 'autocommit' flag set to
True.
autocommitTN)r r rJ s r; r> zSelectBase.autocommit s- #'"9"?"?
4 #
#
rE c | j | j }| j |_ | |S )zWOverride the default _generate() method to also clear out
exported collections.)r r r copyr )rK ss r; _generatezSelectBase._generate sG
N " "4> 2 2]''))
rE c | gS r> rQ rJ s r; r zSelectBase._from_objects r rE N)
rM rN rO ri r r r
r, r r> rB rP r rQ rE r; rA rA h s " " " , , , T_
8
[
X rE rA c e Zd ZdZ e Z e ZdZdZdZ ddZ
e d Z e j
d Z e dd Zed Ze d Ze d
Ze d Ze d Zed
Zed Zed Zed Zd Zd Ze d Ze fdZ dS )GenerativeSelectaZ Base class for SELECT statements where additional elements can be
added.
This serves as the base for :class:`_expression.Select` and
:class:`_selectable.CompoundSelect`
where elements such as ORDER BY, GROUP BY can be added and column
rendering can be controlled. Compare to :class:`.TextAsFrom`, which,
while it subclasses :class:`_expression.SelectBase`
and is also a SELECT construct,
represents a fixed textual string which cannot be altered at this level,
only wrapped as a subquery.
.. versionadded:: 0.9.0 :class:`_expression.GenerativeSelect` was added to
provide functionality specific to :class:`_expression.Select` and
:class:`_selectable.CompoundSelect` while allowing
:class:`_expression.SelectBase` to be
used for other SELECT-like objects, e.g. :class:`.TextAsFrom`.
NFc || _ |dur t | | _ |5t j d | j d|i | _ |t | | _ |t | | _
|| _ |(t t j
| dt i| _ |*t t j
| dt i| _ d S d S )NFzThe select.autocommit parameter is deprecated and will be removed in a future release. Please refer to the Select.execution_options.autocommit` parameter.r> r )r r! r' _for_update_argr, warn_deprecatedr r rZ
_limit_clause_offset_clause_bindr$ r5 r _order_by_clauser _group_by_clause) rK r
for_updatelimitoffsetorder_bygroup_byr r> s r; r' zGenerativeSelect.__init__ s % U " "#/#C#CJ#O#OD ! B
'+&=&C&C z*' 'D # !8!?!?D "9&"A"AD
$. h''%!G% %D ! $. h''%!<% %D ! ! ! rE c , | j | j j S dS )z@Provide legacy dialect support for the ``for_update`` attribute.N)rG r) rJ s r; rN zGenerativeSelect.for_update s +'? ?4rE c D t | | _ d S r> )r! r' rG )rK rY s r; rN zGenerativeSelect.for_update s + ? ? F F rE c 8 t ||||| | _ dS )a Specify a ``FOR UPDATE`` clause for this
:class:`_expression.GenerativeSelect`.
E.g.::
stmt = select([table]).with_for_update(nowait=True)
On a database like PostgreSQL or Oracle, the above would render a
statement like::
SELECT table.a, table.b FROM table FOR UPDATE NOWAIT
on other backends, the ``nowait`` option is ignored and instead
would produce::
SELECT table.a, table.b FROM table FOR UPDATE
When called with no arguments, the statement will render with
the suffix ``FOR UPDATE``. Additional arguments can then be
provided which allow for common database-specific
variants.
:param nowait: boolean; will render ``FOR UPDATE NOWAIT`` on Oracle
and PostgreSQL dialects.
:param read: boolean; will render ``LOCK IN SHARE MODE`` on MySQL,
``FOR SHARE`` on PostgreSQL. On PostgreSQL, when combined with
``nowait``, will render ``FOR SHARE NOWAIT``.
:param of: SQL expression or list of SQL expression elements
(typically :class:`_schema.Column`
objects or a compatible expression) which
will render into a ``FOR UPDATE OF`` clause; supported by PostgreSQL
and Oracle. May render as a table or as a column depending on
backend.
:param skip_locked: boolean, will render ``FOR UPDATE SKIP LOCKED``
on Oracle and PostgreSQL dialects or ``FOR SHARE SKIP LOCKED`` if
``read=True`` is also specified.
.. versionadded:: 1.1.0
:param key_share: boolean, will render ``FOR NO KEY UPDATE``,
or if combined with ``read=True`` will render ``FOR KEY SHARE``,
on the PostgreSQL dialect.
.. versionadded:: 1.1.0
)r# r$ r- r+ r, N)r! rG r6 s r; with_for_updatez GenerativeSelect.with_for_update s1 t ,#
rE c d| _ dS )a Return a new selectable with the 'use_labels' flag set to True.
This will result in column expressions being generated using labels
against their table name, such as "SELECT somecolumn AS
tablename_somecolumn". This allows selectables which contain multiple
FROM clauses to produce a unique set of column names regardless of
name conflicts among the individual FROM clauses.
TN)r rJ s r; apply_labelsz GenerativeSelect.apply_labels? s rE c , t | j d S )zGet an integer value for the limit. This should only be used
by code that cannot support a limit as a BindParameter or
other custom clause as it will throw an exception if the limit
isn't currently set to an integer.
rO )r_ rI rJ s r; _limitzGenerativeSelect._limitL s -T-?IIIrE c 6 t | j t S )zqTrue if the LIMIT clause is a simple integer, False
if it is not present or is a SQL expression.
)r2 rI rG rJ s r; _simple_int_limitz"GenerativeSelect._simple_int_limitV s
$,.?@@@rE c 6 t | j t S )zrTrue if the OFFSET clause is a simple integer, False
if it is not present or is a SQL expression.
)r2 rJ rG rJ s r; _simple_int_offsetz#GenerativeSelect._simple_int_offset] s
$-/@AAArE c , t | j d S )zGet an integer value for the offset. This should only be used
by code that cannot support an offset as a BindParameter or
other custom clause as it will throw an exception if the
offset isn't currently set to an integer.
rP )r_ rJ rJ s r; _offsetzGenerativeSelect._offsetd s -T-@(KKKrE c . t | | _ dS )a1 Return a new selectable with the given LIMIT criterion
applied.
This is a numerical value which usually renders as a ``LIMIT``
expression in the resulting select. Backends that don't
support ``LIMIT`` will attempt to provide similar
functionality.
.. versionchanged:: 1.0.0 - :meth:`_expression.Select.limit` can now
accept arbitrary SQL expressions as well as integer values.
:param limit: an integer LIMIT parameter, or a SQL expression
that provides an integer result.
N)rZ rI )rK rO s r; rO zGenerativeSelect.limitn s $ 5U ; ;rE c . t | | _ dS )a8 Return a new selectable with the given OFFSET criterion
applied.
This is a numeric value which usually renders as an ``OFFSET``
expression in the resulting select. Backends that don't
support ``OFFSET`` will attempt to provide similar
functionality.
.. versionchanged:: 1.0.0 - :meth:`_expression.Select.offset` can now
accept arbitrary SQL expressions as well as integer values.
:param offset: an integer OFFSET parameter, or a SQL expression
that provides an integer result.
N)rZ rJ )rK rP s r; rP zGenerativeSelect.offset s ( 6f = =rE c | j | dS )a Return a new selectable with the given list of ORDER BY
criterion applied.
e.g.::
stmt = select([table]).order_by(table.c.id, table.c.name)
:param \*clauses: a series of :class:`_expression.ColumnElement`
constructs
which will be used to generate an ORDER BY clause.
.. seealso::
:ref:`core_tutorial_ordering`
N)append_order_byrK clausess r; rQ zGenerativeSelect.order_by s & g&&&&rE c | j | dS )a Return a new selectable with the given list of GROUP BY
criterion applied.
e.g.::
stmt = select([table.c.name, func.max(table.c.stat)]).\
group_by(table.c.name)
:param \*clauses: a series of :class:`_expression.ColumnElement`
constructs
which will be used to generate an GROUP BY clause.
.. seealso::
:ref:`core_tutorial_ordering`
N)append_group_byre s r; rR zGenerativeSelect.group_by s ( g&&&&rE c t | dk r |d t | _ dS t | dd $t | j t | z }t |dt
i| _ dS )a Append the given ORDER BY criterion applied to this selectable.
The criterion will be appended to any pre-existing ORDER BY criterion.
This is an **in-place** mutation method; the
:meth:`_expression.GenerativeSelect.order_by` method is preferred,
as it
provides standard :term:`method chaining`.
.. seealso::
:meth:`_expression.GenerativeSelect.order_by`
r r NrL r )r r$ rL r r r re s r; rd z GenerativeSelect.append_order_by s w<<1 !3$.LLD ! ! !t /66B t 455W
E$.%!G% %D ! ! !rE c t | dk r |d t | _ dS t | dd $t | j t | z }t |dt
i| _ dS )a Append the given GROUP BY criterion applied to this selectable.
The criterion will be appended to any pre-existing GROUP BY criterion.
This is an **in-place** mutation method; the
:meth:`_expression.GenerativeSelect.group_by` method is preferred,
as it provides standard :term:`method chaining`.
.. seealso::
:meth:`_expression.GenerativeSelect.group_by`
r r NrM r )r r$ rM r r r re s r; rh z GenerativeSelect.append_group_by s w<<1 !3$.LLD ! ! !t /66B t 455W
E$.%+F% %D ! ! !rE c t r> )r rJ s r; _label_resolve_dictz$GenerativeSelect._label_resolve_dict s !###rE c r | j || j fi || _ | j || j fi || _ d S d S r> )rI rJ rI s r; rK z GenerativeSelect._copy_internals s\ )!&t'9!@!@R!@!@D *"'%(;"B"Br"B"BD + *rE )FFNNNNNNr7 ) rM rN rO ri r$ rL rM rI rJ rG r' rP rN setterr
rV rX rZ r\ r^ r` rO rP rQ rR rd rh rl r rK rQ rE r; rE rE s< ( "z||!z||MNO
( ( ( (T X G G G
?
?
?
[?
B
[
J J XJ A A XA B B XB L L XL < < [<& > > [>* ' ' ['( ' ' ['* 2 . $ $ X$ %+ C C C C C CrE rE c e Zd ZdZdZ ej d Z ej d Z ej d Z ej d Z
ej d Z ej d Z d Z
d
Zed Zed Zed
Zed Zed Zed Zed Zd Zd dZd Zd Zd Z e f fd Z d dZ d Z d Z! ee e! Z xZ"S ) r aX Forms the basis of ``UNION``, ``UNION ALL``, and other
SELECT-based set operations.
.. seealso::
:func:`_expression.union`
:func:`_expression.union_all`
:func:`_expression.intersect`
:func:`_expression.intersect_all`
:func:`_expression.except`
:func:`_expression.except_all`
compound_selectUNIONz UNION ALLEXCEPTz
EXCEPT ALL INTERSECTz
INTERSECT ALLTc
D | dd | _ || _ g | _ d }t | D ]\ }}t | }|st
|j j }ntt
|j j |k rWt j
ddt
| j d j j |dz t
|j j fz | j | | t j | fi | d S )Nr Fz}All selectables passed to CompoundSelect must have identical numbers of columns; select #%d has %d columns, select #%d has %dr r r )rs _auto_correlatekeywordselects enumerater r r r r* r7 r r% rE r' )rK rv rw rd numcolsnrA s r; r' zCompoundSelect.__init__
s( %zz+u = = g&& < rp r9 s r; r< z5CompoundSelect._label_resolve_dict..?
s( ,,!%,,,,,,rE )dictr )rK ds r; rl z"CompoundSelect._label_resolve_dict=
s+ ,,TV,,, , ,!QwrE c 6 t t j g|R i |S )a Return a ``UNION`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
A similar :func:`union()` method is available on all
:class:`_expression.FromClause` subclasses.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r rq r* rw rd s r;
_create_unionz CompoundSelect._create_unionB
s% $ n 2GWGGGGGGrE c 6 t t j g|R i |S )a Return a ``UNION ALL`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
A similar :func:`union_all()` method is available on all
:class:`_expression.FromClause` subclasses.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r UNION_ALLr s r; _create_union_allz CompoundSelect._create_union_allV
s% $ n 6KKKKFKKKrE c 6 t t j g|R i |S )a] Return an ``EXCEPT`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r rr r s r; _create_exceptz CompoundSelect._create_exceptj
s% n 3HgHHHHHHrE c 6 t t j g|R i |S )aa Return an ``EXCEPT ALL`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r
EXCEPT_ALLr s r; _create_except_allz!CompoundSelect._create_except_all{
s% n 7L'LLLVLLLrE c 6 t t j g|R i |S )a` Return an ``INTERSECT`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r rs r s r; _create_intersectz CompoundSelect._create_intersect
s% n 6KKKKFKKKrE c 6 t t j g|R i |S )ad Return an ``INTERSECT ALL`` of multiple selectables.
The returned object is an instance of
:class:`_selectable.CompoundSelect`.
:param \*selects:
a list of :class:`_expression.Select` instances.
:param \**kwargs:
available keyword arguments are the same as those of
:func:`select`.
)r
INTERSECT_ALLr s r; _create_intersect_allz$CompoundSelect._create_intersect_all
s% n :OWOOOOOOrE c @ | j d S Nr )rw _scalar_typerJ s r; r zCompoundSelect._scalar_type
s |A++---rE Nc t | S r> r2 r4 s r; r% zCompoundSelect.self_group
r6 rE c J | j D ]}| | r dS dS NTF)rw r )rK r rA s r; r z CompoundSelect.is_derived_from
s: A ,,
tt
urE c t d | j D D ]f}|d | | j r
|d j nd | j r
|d j nd }d t
| D |_ gd S )Nc & g | ]}|j j S rQ )r r )r~ rA s r; r z>CompoundSelect._populate_column_collection..
s AAAq!#*AAArE r )rX r c H g | ] \ }}| d |dz i S r ) _annotate)r~ r r s r; r z>CompoundSelect._populate_column_collection..
s> 39Aq Xq1u -.. rE )ziprw r r r>
_key_labelrx _proxies)rK r proxys r; r z*CompoundSelect._populate_column_collection
s AADLAAAB D G'''+@T!W^^D*./CDG&&t ( E =Ft__ ENN/ rE c p | j D ]}| | | j sd S t d )NzUCompoundSelect constructs don't support addition of columns to underlying selectables)rw r r
r )rK r rA s r; r z&CompoundSelect._refresh_for_new_column
sQ . .A
% %f - - - -# 4!
rE c B t t | j fi | fd| j D | _ t | d r| `dD ]8}t | | &t | | t | | fi 9d S )Nc " g | ] } |fi S rQ rQ )r~ rA rJ rw s r; r z2CompoundSelect._copy_internals..
s' ===1a2===rE _col_map)rL rM rG ) r r rK r rw rV r r setattr)rK rJ rw r r s `` r; rK z CompoundSelect._copy_internals
s 3nd##3E@@R@@@ ===== === 4 $ $
F FD
tT"".dEE'$*=*=$D$D$D$DEEE
F FrE c z |rt | j pg | j | j gz t | j z S r> )r r rL rM rw r s r; rN zCompoundSelect.get_children
sA
0DLL
6B$d&;<
=4<
!
rE c P | j r| j S | j D ]}|j }|r|c S d S r> )rK rw r )rK rA es r; r zCompoundSelect.bind
sI : : AA
4rE c || _ d S r> rK rK r s r; _set_bindzCompoundSelect._set_bind
rE r> r )#rM rN rO ri rj r, symbolrq r rr r rs r r r' rP rl r r r r r r r r r% r r r r rK rN r r r r s @r; r r s, ( 'N DK E K((I
T[
"
"F \**J K((I DK00M 2 2 2> X H H [H& L L [L& I I [I M M [M L L [L P P [P . . ." " " " 8
%+ F F F F F F
8D) $ $DDDDDrE r c
e Zd ZdZdZdZdZ ej Z dZ
dZ dZ dZ
dZej ZdZ ej dd d6d
Zed Z d7d Zd
Zed Zd8dZed8d Zed Z ej d Z ed Z ed Z d Z!e"f fd Z#d9dZ$ed Z% ej& d d9d Z'ed Z(ed Z)ed Z*ed Z+ed Z,ed! Z-ed" Z.d# Z/d$ Z0d% Z1d& Z2d' Z3d( Z4ed) Z5d* Z6d+ Z7d, Z8d:d-Z9d. Z:d/ Z;d0 Zd3 Z?d4 Z@d5 ZA ee@eA Z@ xZBS );ra z"Represents a ``SELECT`` statement.rB rQ FNT)r< aG The :paramref:`_expression.select.autocommit` parameter is deprecated and will be removed in a future release. Please refer to the :paramref:`.Connection.execution_options.autocommit` parameter in conjunction with the the :meth:`.Executable.execution_options` method in order to affect the autocommit behavior for a statement.)rS zThe :paramref:`_expression.select.for_update` parameter is deprecated and will be removed in a future release. Please refer to the :meth:`_expression.Select.with_for_update` to specify the structure of the ``FOR UPDATE`` clause.)r> rN c || _ |dur/|du rd| _ n#d t j | D | _ |6t j d t j | D | _ nt j | _ t
| }
n?# t $ r2} t j t j
d | Y d} ~ nd} ~ ww xY w|
rkg | _ |D ]`} t | } t | t r | t j } | j | ang | _ |3t' | t j | _ nd| _ |3t' | t j | _ nd| _ |r| | |r| | t3 j | fi | dS ) a Construct a new :class:`_expression.Select`.
Similar functionality is also available via the
:meth:`_expression.FromClause.select` method on any
:class:`_expression.FromClause`.
All arguments which accept :class:`_expression.ClauseElement`
arguments also
accept string arguments, which will be converted as appropriate into
either :func:`_expression.text` or
:func:`_expression.literal_column` constructs.
.. seealso::
:ref:`coretutorial_selecting` - Core Tutorial description of
:func:`_expression.select`.
:param columns:
A list of :class:`_expression.ColumnElement` or
:class:`_expression.FromClause`
objects which will form the columns clause of the resulting
statement. For those objects that are instances of
:class:`_expression.FromClause` (typically :class:`_schema.Table`
or :class:`_expression.Alias`
objects), the :attr:`_expression.FromClause.c`
collection is extracted
to form a collection of :class:`_expression.ColumnElement` objects.
This parameter will also accept :class:`_expression.TextClause`
constructs as
given, as well as ORM-mapped classes.
.. note::
The :paramref:`_expression.select.columns`
parameter is not available
in the method form of :func:`_expression.select`, e.g.
:meth:`_expression.FromClause.select`.
.. seealso::
:meth:`_expression.Select.column`
:meth:`_expression.Select.with_only_columns`
:param whereclause:
A :class:`_expression.ClauseElement`
expression which will be used to form the
``WHERE`` clause. It is typically preferable to add WHERE
criterion to an existing :class:`_expression.Select`
using method chaining
with :meth:`_expression.Select.where`.
.. seealso::
:meth:`_expression.Select.where`
:param from_obj:
A list of :class:`_expression.ClauseElement`
objects which will be added to the
``FROM`` clause of the resulting statement. This is equivalent
to calling :meth:`_expression.Select.select_from`
using method chaining on
an existing :class:`_expression.Select` object.
.. seealso::
:meth:`_expression.Select.select_from`
- full description of explicit
FROM clause specification.
:param autocommit: legacy autocommit parameter.
:param bind=None:
an :class:`_engine.Engine` or :class:`_engine.Connection` instance
to which the
resulting :class:`_expression.Select` object will be bound. The
:class:`_expression.Select`
object will otherwise automatically bind to
whatever :class:`~.base.Connectable` instances can be located within
its contained :class:`_expression.ClauseElement` members.
:param correlate=True:
indicates that this :class:`_expression.Select`
object should have its
contained :class:`_expression.FromClause`
elements "correlated" to an enclosing
:class:`_expression.Select` object.
It is typically preferable to specify
correlations on an existing :class:`_expression.Select`
construct using
:meth:`_expression.Select.correlate`.
.. seealso::
:meth:`_expression.Select.correlate`
- full description of correlation.
:param distinct=False:
when ``True``, applies a ``DISTINCT`` qualifier to the columns
clause of the resulting statement.
The boolean argument may also be a column expression or list
of column expressions - this is a special calling form which
is understood by the PostgreSQL dialect to render the
``DISTINCT ON ()`` syntax.
``distinct`` is also available on an existing
:class:`_expression.Select`
object via the :meth:`_expression.Select.distinct` method.
.. seealso::
:meth:`_expression.Select.distinct`
:param for_update=False:
when ``True``, applies ``FOR UPDATE`` to the end of the
resulting statement.
``for_update`` accepts various string values interpreted by
specific backends, including:
* ``"read"`` - on MySQL, translates to ``LOCK IN SHARE MODE``;
on PostgreSQL, translates to ``FOR SHARE``.
* ``"nowait"`` - on PostgreSQL and Oracle, translates to
``FOR UPDATE NOWAIT``.
* ``"read_nowait"`` - on PostgreSQL, translates to
``FOR SHARE NOWAIT``.
.. seealso::
:meth:`_expression.Select.with_for_update` - improved API for
specifying the ``FOR UPDATE`` clause.
:param group_by:
a list of :class:`_expression.ClauseElement`
objects which will comprise the
``GROUP BY`` clause of the resulting select. This parameter
is typically specified more naturally using the
:meth:`_expression.Select.group_by` method on an existing
:class:`_expression.Select`.
.. seealso::
:meth:`_expression.Select.group_by`
:param having:
a :class:`_expression.ClauseElement`
that will comprise the ``HAVING`` clause
of the resulting select when ``GROUP BY`` is used. This parameter
is typically specified more naturally using the
:meth:`_expression.Select.having` method on an existing
:class:`_expression.Select`.
.. seealso::
:meth:`_expression.Select.having`
:param limit=None:
a numerical value which usually renders as a ``LIMIT``
expression in the resulting select. Backends that don't
support ``LIMIT`` will attempt to provide similar
functionality. This parameter is typically specified more
naturally using the :meth:`_expression.Select.limit`
method on an existing
:class:`_expression.Select`.
.. seealso::
:meth:`_expression.Select.limit`
:param offset=None:
a numeric value which usually renders as an ``OFFSET``
expression in the resulting select. Backends that don't
support ``OFFSET`` will attempt to provide similar
functionality. This parameter is typically specified more naturally
using the :meth:`_expression.Select.offset` method on an existing
:class:`_expression.Select`.
.. seealso::
:meth:`_expression.Select.offset`
:param order_by:
a scalar or list of :class:`_expression.ClauseElement`
objects which will
comprise the ``ORDER BY`` clause of the resulting select.
This parameter is typically specified more naturally using the
:meth:`_expression.Select.order_by` method on an existing
:class:`_expression.Select`.
.. seealso::
:meth:`_expression.Select.order_by`
:param use_labels=False:
when ``True``, the statement will be generated using labels
for each column in the columns clause, which qualify each
column with its parent table's (or aliases) name so that name
conflicts between columns in different tables don't occur.
The format of the label is ``_``. The "c"
collection of the resulting :class:`_expression.Select`
object will use these
names as well for targeting column members.
This parameter can also be specified on an existing
:class:`_expression.Select` object using the
:meth:`_expression.Select.apply_labels`
method.
.. seealso::
:meth:`_expression.Select.apply_labels`
FTc , g | ]}t | S rQ r r~ r s r; r z#Select.__init__.. s0 " " " 022" " "rE Nc 3 4 K | ]}t | V d S r> r< r s r; r< z"Select.__init__.. s< - -*+"1%%- - - - - -rE zDcolumns argument to select() must be a Python list or other iterabler/ r )ru _distinctr, r5
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a Return the full list of 'from' clauses to be displayed.
Takes into account a set of existing froms which may be
rendered in the FROM clause of enclosing selects; this Select
may want to leave those absent if it is automatically
correlating.
c 6 g | ]}t |j S rQ )r r r s r; r z-Select._get_display_froms..v s" K K KnQ] ; ; K K KrE c 3 r K | ]1}j | | "j | V 2d S r> )r r )r~ r rK s r; r< z,Select._get_display_froms..} s[ (+BB1EE %a( rE c g | ]}|v| S rQ rQ )r~ r toremoves r; r z-Select._get_display_froms.. s# ;;;1():):Q):):):rE c X g | ]&}|t t pd v$|'S rQ r )r~ r explicit_correlate_fromsr to_correlates r; r z-Select._get_display_froms.. s`
/, !#;#Ar % rE Nc b g | ]+}|t t pd j v)|,S r )r r _correlate_except)r~ r r r rK s r; r z-Select._get_display_froms.. sc
)( 7 =2 * rE r c 8 g | ]}|t v|S rQ r )r~ r r implicit_correlate_fromss r; r z-Select._get_display_froms.. sI +E3KLLM M M M MrE zSelect statement '%s' returned no FROM clauses due to auto-correlation; specify correlate() to control correlation manually.)
r r rD rE r rC r
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#' ' rE c ^ | j d }t |j }|d j S r )r r r! type)rK r r s r; r zSelect._scalar_type s+ #D)**Aw|rE c * | S )z1Return the displayed list of FromClause elements.)r rJ s r; r z Select.froms s &&(((rE *c 0 | d|| S )a Add a statement hint to this :class:`_expression.Select`.
This method is similar to :meth:`_expression.Select.with_hint`
except that
it does not require an individual table, and instead applies to the
statement as a whole.
Hints here are specific to the backend database and may include
directives such as isolation levels, file directives, fetch directives,
etc.
.. versionadded:: 1.0.0
.. seealso::
:meth:`_expression.Select.with_hint`
:meth:`.Select.prefix_with` - generic SELECT prefixing which also
can suit some database-specific HINT syntaxes such as MySQL
optimizer hints
N) with_hint)rK text dialect_names r; with_statement_hintzSelect.with_statement_hint s . ~~dD,777rE c z || xj ||ffz
c_ dS | j ||f|i | _ dS )a Add an indexing or other executional context hint for the given
selectable to this :class:`_expression.Select`.
The text of the hint is rendered in the appropriate
location for the database backend in use, relative
to the given :class:`_schema.Table` or :class:`_expression.Alias`
passed as the
``selectable`` argument. The dialect implementation
typically uses Python string substitution syntax
with the token ``%(name)s`` to render the name of
the table or alias. E.g. when using Oracle, the
following::
select([mytable]).\
with_hint(mytable, "index(%(name)s ix_mytable)")
Would render SQL as::
select /*+ index(mytable ix_mytable) */ ... from mytable
The ``dialect_name`` option will limit the rendering of a particular
hint to a particular backend. Such as, to add hints for both Oracle
and Sybase simultaneously::
select([mytable]).\
with_hint(mytable, "index(%(name)s ix_mytable)", 'oracle').\
with_hint(mytable, "WITH INDEX ix_mytable", 'sybase')
.. seealso::
:meth:`_expression.Select.with_statement_hint`
N)_statement_hints_hintsr )rK r4 r r s r; r zSelect.with_hint sR F ! !|T&:%< < ! ! ! ! +++j,-G,NOODKKKrE c * t j d )NzvSelect objects don't have a type. Call as_scalar() on this Select object to return a 'scalar' version of this Select.r* r rJ s r; r z Select.type
s %
rE c B | j }|t t | z S )a Return a Set of all :class:`_expression.FromClause` elements
referenced by this Select.
This set is a superset of that returned by the ``froms`` property,
which is specifically for those FromClause elements that would
actually be rendered.
)r r r )rK r s r; locate_all_fromszSelect.locate_all_froms
s# tM5 12222rE c * t | j S )zAn iterator of all :class:`_expression.ColumnElement`
expressions which would
be rendered into the columns clause of the resulting SELECT statement.
)r r rJ s r;
inner_columnszSelect.inner_columns
s !!2333rE c @ t d t | j D }t d t | j D }| }| D ]\ }}| || |||fS )Nc 3 R K | ]"}|j |j p
|j p|j |fV #d S r> )_allow_label_resolve_resolve_labelr> r r9 s r; r< z-Select._label_resolve_dict..)
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NN$$ $**,, - -JC e , , , ,*i//rE c z | |j v rdS | D ]}| | r dS dS r )r r r )rK r r s r; r zSelect.is_derived_from9
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sB ) )#$a2) ) ) ) ) )rE c " g | ] } |fi S rQ rQ )r~ r rJ rw s r; r z*Select._copy_internals..o
s' G G GUU1^^^^ G G GrE )r r rL rM rG )r ra rK r} r r r r r, r r r r r r r r )rK rJ rw r r r s `` @r; rK zSelect._copy_internalsB
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rE c |rt | j pg | j z t | j z d | j | j | j | j fD z S )z=Return child elements as per the ClauseElement specification.c g | ]}||S r> rQ r s r; r z'Select.get_children..
s) = !==rE )r r r r r r rL rM r s r; rN zSelect.get_children~
sy
6D $6$6
<"
4;
%L))
rE c 0 | | dS )a Return a new :func:`_expression.select` construct with
the given column expression added to its columns clause.
E.g.::
my_select = my_select.column(table.c.new_column)
See the documentation for
:meth:`_expression.Select.with_only_columns`
for guidelines on adding /replacing the columns of a
:class:`_expression.Select` object.
N)r r s r; r z
Select.column
s
6"""""rE r c | |j | j g| j ft | j z R d|i S )a Return a new :func:`_expression.select` construct with redundantly
named, equivalently-valued columns removed from the columns clause.
"Redundant" here means two columns where one refers to the
other either based on foreign key, or via a simple equality
comparison in the WHERE clause of the statement. The primary purpose
of this method is to automatically construct a select statement
with all uniquely-named columns, without the need to use
table-qualified labels as :meth:`_expression.Select.apply_labels`
does.
When columns are omitted based on foreign key, the referred-to
column is the one that's kept. When columns are omitted based on
WHERE equivalence, the first column in the columns clause is the
one that's kept.
:param only_synonyms: when True, limit the removal of columns
to those which have the same name as the equivalent. Otherwise,
all columns that are equivalent to another are removed.
only_synonyms)with_only_columnsrB r r r r )rK r r s r; rB zSelect.reduce_columns
se . %% "G ""
#%dn(=(==
+
rE c | g }|D ][}t | }t |t r | t
j }| | \|| _ dS )av
Return a new :func:`_expression.select` construct with its columns
clause replaced with the given columns.
This method is exactly equivalent to as if the original
:func:`_expression.select` had been called with the given columns
clause. I.e. a statement::
s = select([table1.c.a, table1.c.b])
s = s.with_only_columns([table1.c.b])
should be exactly equivalent to::
s = select([table1.c.b])
This means that FROM clauses which are only derived
from the column list will be discarded if the new column
list no longer contains that FROM::
>>> table1 = table('t1', column('a'), column('b'))
>>> table2 = table('t2', column('a'), column('b'))
>>> s1 = select([table1.c.a, table2.c.b])
>>> print(s1)
SELECT t1.a, t2.b FROM t1, t2
>>> s2 = s1.with_only_columns([table2.c.b])
>>> print(s2)
SELECT t2.b FROM t1
The preferred way to maintain a specific FROM clause
in the construct, assuming it won't be represented anywhere
else (i.e. not in the WHERE clause, etc.) is to set it using
:meth:`_expression.Select.select_from`::
>>> s1 = select([table1.c.a, table2.c.b]).\
... select_from(table1.join(table2,
... table1.c.a==table2.c.a))
>>> s2 = s1.with_only_columns([table2.c.b])
>>> print(s2)
SELECT t2.b FROM t1 JOIN t2 ON t1.a=t2.a
Care should also be taken to use the correct set of column objects
passed to :meth:`_expression.Select.with_only_columns`.
Since the method is
essentially equivalent to calling the :func:`_expression.select`
construct in the first place with the given columns, the columns passed
to :meth:`_expression.Select.with_only_columns`
should usually be a subset of
those which were passed to the :func:`_expression.select`
construct, not those which are available from the ``.c`` collection of
that :func:`_expression.select`. That is::
s = select([table1.c.a, table1.c.b]).select_from(table1)
s = s.with_only_columns([table1.c.b])
and **not**::
# usually incorrect
s = s.with_only_columns([s.c.b])
The latter would produce the SQL::
SELECT b
FROM (SELECT t1.a AS a, t1.b AS b
FROM t1), t1
Since the :func:`_expression.select` construct is essentially
being asked to select both from ``table1`` as well as itself.
r N) r r r2 r: r% r r r r )rK r rcr s r; r zSelect.with_only_columns
s L
A,Q//A!\**
=LL);L<< IIaLLLL rE c 0 | | dS )zReturn a new :func:`_expression.select` construct with
the given expression added to
its WHERE clause, joined to the existing clause via AND, if any.
N)append_whereclauserK r s r; wherez Select.where s
,,,,,rE c 0 | | dS )zReturn a new :func:`_expression.select` construct with
the given expression added to
its HAVING clause, joined to the existing clause via AND, if any.
N)
append_havingrK r s r; r z
Select.having s
6"""""rE c |r@d |D }t | j t r| j |z | _ dS || _ dS d| _ dS )a Return a new :func:`_expression.select` construct which
will apply DISTINCT to its columns clause.
:param \*expr: optional column expressions. When present,
the PostgreSQL dialect will render a ``DISTINCT ON (>)``
construct.
c , g | ]}t | S rQ r r s r; r z#Select.distinct... s! AAAq/22AAArE TN)r2 r r )rK rn s r; r zSelect.distinct# s[ "AADAAAD$.$//
&!% $!6!% !DNNNrE c 0 | | dS )a Return a new :func:`_expression.select` construct with the
given FROM expression(s)
merged into its list of FROM objects.
E.g.::
table1 = table('t1', column('a'))
table2 = table('t2', column('b'))
s = select([table1.c.a]).\
select_from(
table1.join(table2, table1.c.a==table2.c.b)
)
The "from" list is a unique set on the identity of each element,
so adding an already present :class:`_schema.Table`
or other selectable
will have no effect. Passing a :class:`_expression.Join` that refers
to an already present :class:`_schema.Table`
or other selectable will have
the effect of concealing the presence of that selectable as
an individual element in the rendered FROM list, instead
rendering it into a JOIN clause.
While the typical purpose of :meth:`_expression.Select.select_from`
is to
replace the default, derived FROM clause with a join, it can
also be called with individual table elements, multiple times
if desired, in the case that the FROM clause cannot be fully
derived from the columns clause::
select([func.count('*')]).select_from(table1)
N) append_fromr s r; select_fromzSelect.select_from6 s F
$$$$$rE c d| _ |r|d d| _ dS t | j d |D | _ dS )aU Return a new :class:`_expression.Select`
which will correlate the given FROM
clauses to that of an enclosing :class:`_expression.Select`.
Calling this method turns off the :class:`_expression.Select` object's
default behavior of "auto-correlation". Normally, FROM elements
which appear in a :class:`_expression.Select`
that encloses this one via
its :term:`WHERE clause`, ORDER BY, HAVING or
:term:`columns clause` will be omitted from this
:class:`_expression.Select`
object's :term:`FROM clause`.
Setting an explicit correlation collection using the
:meth:`_expression.Select.correlate`
method provides a fixed list of FROM objects
that can potentially take place in this process.
When :meth:`_expression.Select.correlate`
is used to apply specific FROM clauses
for correlation, the FROM elements become candidates for
correlation regardless of how deeply nested this
:class:`_expression.Select`
object is, relative to an enclosing :class:`_expression.Select`
which refers to
the same FROM object. This is in contrast to the behavior of
"auto-correlation" which only correlates to an immediate enclosing
:class:`_expression.Select`.
Multi-level correlation ensures that the link
between enclosed and enclosing :class:`_expression.Select`
is always via
at least one WHERE/ORDER BY/HAVING/columns clause in order for
correlation to take place.
If ``None`` is passed, the :class:`_expression.Select`
object will correlate
none of its FROM entries, and all will render unconditionally
in the local FROM clause.
:param \*fromclauses: a list of one or more
:class:`_expression.FromClause`
constructs, or other compatible constructs (i.e. ORM-mapped
classes) to become part of the correlate collection.
.. seealso::
:meth:`_expression.Select.correlate_except`
:ref:`correlated_subqueries`
Fr NrQ c 3 4 K | ]}t | V d S r> r r s r; r< z#Select.correlate.. s< 9 9*+"1%%9 9 9 9 9 9rE )ru r r r rK fromclausess r; r zSelect.correlate[ sj j % ;q>1 DOOO !$/ 2 2 8 8 9 9/:9 9 9 DOOOrE c d| _ |r|d d| _ dS t | j pd d |D | _ dS )a Return a new :class:`_expression.Select`
which will omit the given FROM
clauses from the auto-correlation process.
Calling :meth:`_expression.Select.correlate_except` turns off the
:class:`_expression.Select` object's default behavior of
"auto-correlation" for the given FROM elements. An element
specified here will unconditionally appear in the FROM list, while
all other FROM elements remain subject to normal auto-correlation
behaviors.
If ``None`` is passed, the :class:`_expression.Select`
object will correlate
all of its FROM entries.
:param \*fromclauses: a list of one or more
:class:`_expression.FromClause`
constructs, or other compatible constructs (i.e. ORM-mapped
classes) to become part of the correlate-exception collection.
.. seealso::
:meth:`_expression.Select.correlate`
:ref:`correlated_subqueries`
Fr NrQ c 3 4 K | ]}t | V d S r> r r s r; r< z*Select.correlate_except.. sD M M*+"1%%M M M M M MrE )ru r r r r s r; correlate_exceptzSelect.correlate_except sz < % ;q>1%'D " " "%()?)E2%F%F%L%L M M/:M M M & &D " " "rE c d| _ t | j d |D | _ dS )a Append the given correlation expression to this
:func:`_expression.select` construct.
This is an **in-place** mutation method; the
:meth:`_expression.Select.correlate` method is preferred,
as it provides standard :term:`method chaining`.
Fc 3 4 K | ]}t | V d S r> r r s r; r< z,Select.append_correlation.. s< 5
5
&' q ! !5
5
5
5
5
5
rE N)ru r r r r s r; append_correlationzSelect.append_correlation sM % do..44 5
5
+55
5
5
rE c | t | }t |t r | t
j }| j |gz | _ dS )a- Append the given column expression to the columns clause of this
:func:`_expression.select` construct.
E.g.::
my_select.append_column(some_table.c.new_column)
This is an **in-place** mutation method; the
:meth:`_expression.Select.column` method is preferred,
as it provides standard :term:`method chaining`.
See the documentation for :meth:`_expression.Select.with_only_columns`
for guidelines on adding /replacing the columns of a
:class:`_expression.Select` object.
r N)r r r2 r: r% r r r r s r; r zSelect.append_column sg "
-f55 fl + + C&&y/A&BBF - 8rE c D t | }| j |fz | _ dS )a$ Append the given columns clause prefix expression to this
:func:`_expression.select` construct.
This is an **in-place** mutation method; the
:meth:`_expression.Select.prefix_with` method is preferred,
as it provides standard :term:`method chaining`.
N)r r )rK r] s r;
append_prefixzSelect.append_prefix s% "&)) 6)3rE c | t t j | j | | _ dS )af Append the given expression to this :func:`_expression.select`
construct's WHERE criterion.
The expression will be joined to existing WHERE criterion via AND.
This is an **in-place** mutation method; the
:meth:`_expression.Select.where` method is preferred,
as it provides standard :term:`method chaining`.
N)r r! r' _ifnoner r s r; r zSelect.append_whereclause s;
t/@!A!A; O OrE c | t t j | j | | _ dS )ai Append the given expression to this :func:`_expression.select`
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as it provides standard :term:`method chaining`.
N)r r! r' r r r s r; r zSelect.append_having s7
EM$, 7 7@@ rE c | t | }| j |g | _ dS )a' Append the given FromClause expression to this
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rE c v t |t r| s| S t | S )a@ Return a 'grouping' construct as per the
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expressions and should not require explicit use.
)r2 r r r3 r4 s r; r% zSelect.self_group[ s?
w / / 3355 KD!!!rE c ( t j | |fi |S )zaReturn a SQL ``UNION`` of this select() construct against
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s = select([table.c.col1]).where(table.c.col2==5)
s_e = exists(s)
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# to produce a WHERE EXISTS (SELECT ... )
select([table.c.col1]).where(s_e)
# but can also be used in a select to produce a
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select([s_e])
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The :class:`.TextAsFrom` construct is produced via the
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method - see that method for details.
.. versionadded:: 0.9.0
.. seealso::
:func:`_expression.text`
:meth:`_expression.TextClause.columns`
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,]EBB )!(M ) ) ) )r after_parent_attachc t |t rt j |d fd d S t |t rEt j t s j t u rd S t | }|r | _ d S d S d S )Nr c $ t | S r )_constraint_name)r0 r r s r z"_constraint_name.. s /u = = r ) r r r listenr r r r ry )r r r~ s ` r r r s % ! ! = = = =
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|oiӢ d Z ddlmZ ddlmZ ddlmZ ddlmZ ddlmZ ddlm Z dd lm
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Z G d d e Z G d d!e Z G d" d#e Z G d$ d%e Z G d& d'e Z G d( d)e Z G d* d+e Z G d, d-e Z G d. d/e Z G d0 d1e Z G d2 d3e Z G d4 d5e Z! G d6 d7e! Z" G d8 d9e! Z# d>d;Z$ d?d=Z%d:S )@zq
Provides the hierarchy of DDL-defining schema items as well as routines
to invoke them for a create/drop call.
)_bind_or_error) _generative)
Executable)
SchemaVisitor)
ClauseElement )event)exc)util) topologicalc e Zd Zd ZdS ) _DDLCompilesc |j || fi |S )zNReturn a compiler appropriate for this ClauseElement, given a
Dialect.) ddl_compiler)selfdialectkws I/opt/cloudlinux/venv/lib64/python3.11/site-packages/sqlalchemy/sql/ddl.py _compilerz_DDLCompiles._compiler s! $w#GT88R888 N)__name__
__module__ __qualname__r r r r r s# 9 9 9 9 9r r c e Zd ZdZej ddi ZdZdZdZ dZ
d Z ddZ e
j dd d Zed
Zedd Zd Zd
Zd Zd Zd Zd Z eee Zd ZdS )
DDLElementa Base class for DDL expression constructs.
This class is the base for the general purpose :class:`.DDL` class,
as well as the various create/drop clause constructs such as
:class:`.CreateTable`, :class:`.DropTable`, :class:`.AddConstraint`,
etc.
:class:`.DDLElement` integrates closely with SQLAlchemy events,
introduced in :ref:`event_toplevel`. An instance of one is
itself an event receiving callable::
event.listen(
users,
'after_create',
AddConstraint(constraint).execute_if(dialect='postgresql')
)
.. seealso::
:class:`.DDL`
:class:`.DDLEvents`
:ref:`event_toplevel`
:ref:`schema_ddl_sequences`
autocommitTNc 0 | | || S N) _execute_ddl)r
connection multiparamsparamss r _execute_on_connectionz!DDLElement._execute_on_connectionG s &&t[&AAAr c |t | }| || r(| | | S |j j d dS )a1 Execute this DDL immediately.
Executes the DDL statement in isolation using the supplied
:class:`.Connectable` or
:class:`.Connectable` assigned to the ``.bind``
property, if not supplied. If the DDL has a conditional ``on``
criteria, it will be invoked with None as the event.
:param bind:
Optional, an ``Engine`` or ``Connection``. If not supplied, a valid
:class:`.Connectable` must be present in the
``.bind`` property.
:param target:
Optional, defaults to None. The target :class:`_schema.SchemaItem`
for the execute call. Will be passed to the ``on`` callable if any,
and may also provide string expansion data for the statement.
See ``execute_at`` for more information.
Nz(DDL execution skipped, criteria not met.)r _should_executeexecuteagainstengineloggerinfo)r bindtargets r r' zDDLElement.executeJ sm , <!$''D - - P<< V 4 455 5 K # #$N O O O O Or 0.7zThe :meth:`.DDLElement.execute_at` method is deprecated and will be removed in a future release. Please use the :class:`.DDLEvents` listener interface in conjunction with the :meth:`.DDLElement.execute_if` method.c p fd}t j |d dd z | dS )a_ Link execution of this DDL to the DDL lifecycle of a SchemaItem.
Links this ``DDLElement`` to a ``Table`` or ``MetaData`` instance,
executing it when that schema item is created or dropped. The DDL
statement will be executed using the same Connection and transactional
context as the Table create/drop itself. The ``.bind`` property of
this statement is ignored.
:param event:
One of the events defined in the schema item's ``.ddl_events``;
e.g. 'before-create', 'after-create', 'before-drop' or 'after-drop'
:param target:
The Table or MetaData instance for which this DDLElement will
be associated with.
A DDLElement instance can be linked to any number of schema items.
``execute_at`` builds on the ``append_ddl_listener`` interface of
:class:`_schema.MetaData` and :class:`_schema.Table` objects.
Caveat: Creating or dropping a Table in isolation will also trigger
any DDL set to ``execute_at`` that Table's MetaData. This may change
in a future release.
c x j | |fi |r(| | S d S r )_should_execute_deprecatedr' r( )r- r! r
event_namer s r
call_eventz)DDLElement.execute_at..call_event s] .t.FJ 24
@ "))$,,v*>*>???
@
@r -_N)r listenreplace)r r2 r- r3 s `` r
execute_atzDDLElement.execute_ath sZ F @ @ @ @ @ @ VR*"4"4S#">"> >
KKKKKr c || _ dS )z9Return a copy of this DDL against a specific schema item.N)r- )r r- s r r( zDDLElement.against s r c 0 || _ || _ || _ dS )a Return a callable that will execute this
DDLElement conditionally.
Used to provide a wrapper for event listening::
event.listen(
metadata,
'before_create',
DDL("my_ddl").execute_if(dialect='postgresql')
)
:param dialect: May be a string, tuple or a callable
predicate. If a string, it will be compared to the name of the
executing database dialect::
DDL('something').execute_if(dialect='postgresql')
If a tuple, specifies multiple dialect names::
DDL('something').execute_if(dialect=('postgresql', 'mysql'))
:param callable\_: A callable, which will be invoked with
four positional arguments as well as optional keyword
arguments:
:ddl:
This DDL element.
:target:
The :class:`_schema.Table` or :class:`_schema.MetaData`
object which is the
target of this event. May be None if the DDL is executed
explicitly.
:bind:
The :class:`_engine.Connection` being used for DDL execution
:tables:
Optional keyword argument - a list of Table objects which are to
be created/ dropped within a MetaData.create_all() or drop_all()
method call.
:state:
Optional keyword argument - will be the ``state`` argument
passed to this function.
:checkfirst:
Keyword argument, will be True if the 'checkfirst' flag was
set during the call to ``create()``, ``create_all()``,
``drop()``, ``drop_all()``.
If the callable returns a True value, the DDL statement will be
executed.
:param state: any value which will be passed to the callable\_
as the ``state`` keyword argument.
.. seealso::
:class:`.DDLEvents`
:ref:`event_toplevel`
N)r callable_state)r r r< r= s r
execute_ifzDDLElement.execute_if s D "
r c ^ | j | j d ||fi |sdS t | j t j r| j |j j k rdS n %ndn &$/
/
&*j/
46/
/
% 5tr c | j dS t | j t j r| j |j j k S t | j t t t f r|j j | j v S | j | |||fi |S NT) r@ rA r rB r) rC rD rE rF )r r r- r, r s r r1 z%DDLElement._should_execute_deprecated s 7?4
!2
3
3 <7dk .. .
%s!3
4
4 <;#tw. .474;;;; ;r c t | j ||fi |r(| | | S dS )z"Execute the DDL as a ddl_listener.N)r& r' r( rG s r __call__zDDLElement.__call__ sK 4 3 3 3 3 6<< V 4 455 5 6 6r c |lt |t j t t t
fz s?t j | s-t j dt | j
z d S d S d S )NzjExpected the name of a database dialect, a tuple of names, or a callable for 'on' criteria, got type '%s'.) rA r rB rD rE rF callabler
ArgumentErrortyper )r r@ s r
_check_ddl_onzDDLElement._check_ddl_on sw
>2t 0E43E EFF M"%% #026r((2CD
>>>>>r c " | j r| j S d S r _bindr s r r, zDDLElement.bind
s : : r c || _ d S r rR )r r, s r _set_bindzDDLElement._set_bind s
r c | j | j }| j |_ |S r ) __class____new____dict__copy)r ss r _generatezDDLElement._generate s3 N " "4> 2 2]''))
r NNNNN)r r r __doc__r _execution_optionsunionr- r@ r r< r$ r' r
deprecatedr9 r r( r> r& r1 rK rP r, rV propertyr] r r r r r su : $6<< t F
BGIB B B P P P P< T_
1 "L "L "LH [
C C C [CJ &< < <6 6 6 8D) $ $D r r c R e Zd ZdZdZ ej d dd Zd ZdS ) DDLaA A literal DDL statement.
Specifies literal SQL DDL to be executed by the database. DDL objects
function as DDL event listeners, and can be subscribed to those events
listed in :class:`.DDLEvents`, using either :class:`_schema.Table` or
:class:`_schema.MetaData` objects as targets.
Basic templating support allows
a single DDL instance to handle repetitive tasks for multiple tables.
Examples::
from sqlalchemy import event, DDL
tbl = Table('users', metadata, Column('uid', Integer))
event.listen(tbl, 'before_create', DDL('DROP TRIGGER users_trigger'))
spow = DDL('ALTER TABLE %(table)s SET secretpowers TRUE')
event.listen(tbl, 'after_create', spow.execute_if(dialect='somedb'))
drop_spow = DDL('ALTER TABLE users SET secretpowers FALSE')
connection.execute(drop_spow)
When operating on Table events, the following ``statement``
string substitutions are available::
%(table)s - the Table name, with any required quoting applied
%(schema)s - the schema name, with any required quoting applied
%(fullname)s - the Table name including schema, quoted if needed
The DDL's "context", if any, will be combined with the standard
substitutions noted above. Keys present in the context will override
the standard substitutions.
ddl)r. zThe :paramref:`.DDL.on` parameter is deprecated and will be removed in a future release. Please refer to :meth:`.DDLElement.execute_if`.)r@ Nc t |t j st j d|z || _ |pi | _ | | || _ || _ dS )a) Create a DDL statement.
:param statement:
A string or unicode string to be executed. Statements will be
processed with Python's string formatting operator. See the
``context`` argument and the ``execute_at`` method.
A literal '%' in a statement must be escaped as '%%'.
SQL bind parameters are not available in DDL statements.
:param on:
Optional filtering criteria. May be a string, tuple or a callable
predicate. If a string, it will be compared to the name of the
executing database dialect::
DDL('something', on='postgresql')
If a tuple, specifies multiple dialect names::
DDL('something', on=('postgresql', 'mysql'))
If a callable, it will be invoked with four positional arguments
as well as optional keyword arguments:
:ddl:
This DDL element.
:event:
The name of the event that has triggered this DDL, such as
'after-create' Will be None if the DDL is executed explicitly.
:target:
The ``Table`` or ``MetaData`` object which is the target of
this event. May be None if the DDL is executed explicitly.
:connection:
The ``Connection`` being used for DDL execution
:tables:
Optional keyword argument - a list of Table objects which are to
be created/ dropped within a MetaData.create_all() or drop_all()
method call.
If the callable returns a true value, the DDL statement will be
executed.
:param context:
Optional dictionary, defaults to None. These values will be
available for use in string substitutions on the DDL statement.
:param bind:
Optional. A :class:`.Connectable`, used by
default when ``execute()`` is invoked without a bind argument.
.. seealso::
:class:`.DDLEvents`
:ref:`event_toplevel`
z4Expected a string or unicode SQL statement, got '%r'N)
rA r rB r
rN statementcontextrP r@ rS )r ri r@ rj r, s r __init__z DDL.__init__B st V )T%677 #F
# }" 2
r c
dt j dt dd t j g fddD z dS )N<@z; , c Z g | ]'}t | |d t | (S )=)getattr).0keyr s r
z DDL.__repr__.. sO tS)) "ssGD#$6$6$67 r )r@ rj >)rO r idjoinreprri rT s `r __repr__z DDL.__repr__ s JJ tHHHH IIdn%%& 0
r r_ ) r r r r` __visit_name__r deprecated_paramsrk rz r r r rf rf st ! !F NT
N N N N`
r rf c e Zd ZdZddZd ZdS )_CreateDropBasezBase class for DDL constructs that represent CREATE and DROP or
equivalents.
The common theme of _CreateDropBase is a single
``element`` attribute which refers to the element
to be created or dropped.
Nc Z || _ | | || _ || _ d S r )elementrP r@ r, )r r r@ r, s r rk z_CreateDropBase.__init__ s/ 2 r c dS )zAllow disable of _create_rule using a callable.
Pass to _create_rule using
util.portable_instancemethod(self._create_rule_disable)
to retain serializability.
Fr )r compilers r _create_rule_disablez$_CreateDropBase._create_rule_disable s ur r^ )r r r r` rk r r r r r~ r~ sA r r~ c ( e Zd ZdZdZd fd Z xZS ) CreateSchemazcRepresent a CREATE SCHEMA statement.
The argument here is the string name of the schema.
create_schemaNc X || _ t t | j |fi | dS )z.Create a new :class:`.CreateSchema` construct.N)quotesuperr rk )r rC r r rX s r rk zCreateSchema.__init__ s7
*lD!!*466266666r r r r r r` r{ rk
__classcell__rX s @r r r sN %N7 7 7 7 7 7 7 7 7 7r r c ( e Zd ZdZdZd fd Z xZS )
DropSchemazaRepresent a DROP SCHEMA statement.
The argument here is the string name of the schema.
drop_schemaNFc f || _ || _ t t | j |fi | dS )z,Create a new :class:`.DropSchema` construct.N)r cascader r rk )r rC r r r rX s r rk zDropSchema.__init__ s>
(j$ (4444444r NFr r s @r r r sN #N5 5 5 5 5 5 5 5 5 5r r c * e Zd ZdZdZ d fd Z xZS ) CreateTablez#Represent a CREATE TABLE statement. create_tableNc t t | ||| d |j D | _ || _ dS )aZ Create a :class:`.CreateTable` construct.
:param element: a :class:`_schema.Table` that's the subject
of the CREATE
:param on: See the description for 'on' in :class:`.DDL`.
:param bind: See the description for 'bind' in :class:`.DDL`.
:param include_foreign_key_constraints: optional sequence of
:class:`_schema.ForeignKeyConstraint` objects that will be included
inline within the CREATE construct; if omitted, all foreign key
constraints that do not specify use_alter=True are included.
.. versionadded:: 1.0.0
)r@ r, c , g | ]}t | S r ) CreateColumn)rs columns r ru z(CreateTable.__init__.. s KKK V,,KKKr N)r r rk columns include_foreign_key_constraints)r r r@ r, r rX s r rk zCreateTable.__init__ sO " k4 ))'bt)DDDKK7?KKK /N,,,r r_ r r s @r r r sY --#N LPO O O O O O O O O Or r c e Zd ZdZdZdS ) _DropViewzSemi-public 'DROP VIEW' construct.
Used by the test suite for dialect-agnostic drops of views.
This object will eventually be part of a public "view" API.
drop_viewNr r r r` r{ r r r r r s !NNNr r c e Zd ZdZdZd ZdS )r a Represent a :class:`_schema.Column`
as rendered in a CREATE TABLE statement,
via the :class:`.CreateTable` construct.
This is provided to support custom column DDL within the generation
of CREATE TABLE statements, by using the
compiler extension documented in :ref:`sqlalchemy.ext.compiler_toplevel`
to extend :class:`.CreateColumn`.
Typical integration is to examine the incoming :class:`_schema.Column`
object, and to redirect compilation if a particular flag or condition
is found::
from sqlalchemy import schema
from sqlalchemy.ext.compiler import compiles
@compiles(schema.CreateColumn)
def compile(element, compiler, **kw):
column = element.element
if "special" not in column.info:
return compiler.visit_create_column(element, **kw)
text = "%s SPECIAL DIRECTIVE %s" % (
column.name,
compiler.type_compiler.process(column.type)
)
default = compiler.get_column_default_string(column)
if default is not None:
text += " DEFAULT " + default
if not column.nullable:
text += " NOT NULL"
if column.constraints:
text += " ".join(
compiler.process(const)
for const in column.constraints)
return text
The above construct can be applied to a :class:`_schema.Table`
as follows::
from sqlalchemy import Table, Metadata, Column, Integer, String
from sqlalchemy import schema
metadata = MetaData()
table = Table('mytable', MetaData(),
Column('x', Integer, info={"special":True}, primary_key=True),
Column('y', String(50)),
Column('z', String(20), info={"special":True})
)
metadata.create_all(conn)
Above, the directives we've added to the :attr:`_schema.Column.info`
collection
will be detected by our custom compilation scheme::
CREATE TABLE mytable (
x SPECIAL DIRECTIVE INTEGER NOT NULL,
y VARCHAR(50),
z SPECIAL DIRECTIVE VARCHAR(20),
PRIMARY KEY (x)
)
The :class:`.CreateColumn` construct can also be used to skip certain
columns when producing a ``CREATE TABLE``. This is accomplished by
creating a compilation rule that conditionally returns ``None``.
This is essentially how to produce the same effect as using the
``system=True`` argument on :class:`_schema.Column`, which marks a column
as an implicitly-present "system" column.
For example, suppose we wish to produce a :class:`_schema.Table`
which skips
rendering of the PostgreSQL ``xmin`` column against the PostgreSQL
backend, but on other backends does render it, in anticipation of a
triggered rule. A conditional compilation rule could skip this name only
on PostgreSQL::
from sqlalchemy.schema import CreateColumn
@compiles(CreateColumn, "postgresql")
def skip_xmin(element, compiler, **kw):
if element.element.name == 'xmin':
return None
else:
return compiler.visit_create_column(element, **kw)
my_table = Table('mytable', metadata,
Column('id', Integer, primary_key=True),
Column('xmin', Integer)
)
Above, a :class:`.CreateTable` construct will generate a ``CREATE TABLE``
which only includes the ``id`` column in the string; the ``xmin`` column
will be omitted, but only against the PostgreSQL backend.
create_columnc || _ d S r )r )r r s r rk zCreateColumn.__init__t s
r N)r r r r` r{ rk r r r r r s7 d dL %N r r c e Zd ZdZdZdS ) DropTablez!Represent a DROP TABLE statement.
drop_tableNr r r r r r x ++!NNNr r c e Zd ZdZdZdS )CreateSequencez&Represent a CREATE SEQUENCE statement.create_sequenceNr r r r r r ~ s 00&NNNr r c e Zd ZdZdZdS ) DropSequencez$Represent a DROP SEQUENCE statement.
drop_sequenceNr r r r r r s ..$NNNr r c e Zd ZdZdZdS ) CreateIndexz#Represent a CREATE INDEX statement. create_indexNr r r r r r s --#NNNr r c e Zd ZdZdZdS ) DropIndexz!Represent a DROP INDEX statement.
drop_indexNr r r r r r r r r c & e Zd ZdZdZ fdZ xZS )
AddConstraintz2Represent an ALTER TABLE ADD CONSTRAINT statement.add_constraintc t t | j |g|R i | t j | j |_ d S r )r r rk r portable_instancemethodr _create_rule)r r argsr rX s r rk zAddConstraint.__init__ sQ +mT""+GAdAAAbAAA # ; %
r r r s @r r r sC <<%N
r r c ( e Zd ZdZdZd fd Z xZS )DropConstraintz3Represent an ALTER TABLE DROP CONSTRAINT statement.drop_constraintFc || _ t t | j |fi | t j | j |_ d S r )r r r rk r r r r )r r r r rX s r rk zDropConstraint.__init__ sP ,nd##,W;;;;; # ; %
r Fr r s @r r r sH ==&N
r r c e Zd ZdZdZdS )SetTableCommentz*Represent a COMMENT ON TABLE IS statement.set_table_commentNr r r r r r s 44(NNNr r c e Zd ZdZdZdS )DropTableCommentzfRepresent a COMMENT ON TABLE '' statement.
Note this varies a lot across database backends.
drop_table_commentNr r r r r r s *NNNr r c e Zd ZdZdZdS )SetColumnCommentz+Represent a COMMENT ON COLUMN IS statement.set_column_commentNr r r r r r s 55)NNNr r c e Zd ZdZdZdS )DropColumnCommentz0Represent a COMMENT ON COLUMN IS NULL statement.drop_column_commentNr r r r r r s ::*NNNr r c e Zd Zd ZdS )DDLBasec || _ d S r )r! )r r! s r rk zDDLBase.__init__ s
$r N)r r r rk r r r r r s# % % % % %r r c V e Zd Z d fd Zd Zd Zd Z d dZd Zd
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.. versionadded:: 1.0.0
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:func:`.sort_tables`
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way adding extra arguments to the
:attr:`.DefaultDialect.construct_arguments` dictionary. This
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.. versionadded:: 0.9.2
.. versionchanged:: 0.9.4 The :attr:`.DialectKWArgs.dialect_kwargs`
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