268 lines
7.8 KiB
Python
268 lines
7.8 KiB
Python
# orm/__init__.py
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# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""
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Functional constructs for ORM configuration.
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See the SQLAlchemy object relational tutorial and mapper configuration
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documentation for an overview of how this module is used.
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"""
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from . import exc
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from .mapper import (
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Mapper,
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_mapper_registry,
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class_mapper,
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configure_mappers,
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reconstructor,
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validates
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)
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from .interfaces import (
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EXT_CONTINUE,
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EXT_STOP,
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PropComparator,
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)
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from .deprecated_interfaces import (
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MapperExtension,
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SessionExtension,
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AttributeExtension,
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)
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from .util import (
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aliased,
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join,
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object_mapper,
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outerjoin,
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polymorphic_union,
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was_deleted,
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with_parent,
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with_polymorphic,
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)
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from .properties import ColumnProperty
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from .relationships import RelationshipProperty
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from .descriptor_props import (
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ComparableProperty,
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CompositeProperty,
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SynonymProperty,
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)
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from .relationships import (
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foreign,
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remote,
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)
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from .session import (
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Session,
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object_session,
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sessionmaker,
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make_transient
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)
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from .scoping import (
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scoped_session
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)
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from . import mapper as mapperlib
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from .query import AliasOption, Query, Bundle
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from ..util.langhelpers import public_factory
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from .. import util as _sa_util
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from . import strategies as _strategies
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def create_session(bind=None, **kwargs):
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"""Create a new :class:`.Session`
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with no automation enabled by default.
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This function is used primarily for testing. The usual
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route to :class:`.Session` creation is via its constructor
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or the :func:`.sessionmaker` function.
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:param bind: optional, a single Connectable to use for all
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database access in the created
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:class:`~sqlalchemy.orm.session.Session`.
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:param \*\*kwargs: optional, passed through to the
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:class:`.Session` constructor.
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:returns: an :class:`~sqlalchemy.orm.session.Session` instance
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The defaults of create_session() are the opposite of that of
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:func:`sessionmaker`; ``autoflush`` and ``expire_on_commit`` are
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False, ``autocommit`` is True. In this sense the session acts
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more like the "classic" SQLAlchemy 0.3 session with these.
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Usage::
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>>> from sqlalchemy.orm import create_session
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>>> session = create_session()
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It is recommended to use :func:`sessionmaker` instead of
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create_session().
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"""
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kwargs.setdefault('autoflush', False)
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kwargs.setdefault('autocommit', True)
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kwargs.setdefault('expire_on_commit', False)
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return Session(bind=bind, **kwargs)
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relationship = public_factory(RelationshipProperty, ".orm.relationship")
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def relation(*arg, **kw):
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"""A synonym for :func:`relationship`."""
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return relationship(*arg, **kw)
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def dynamic_loader(argument, **kw):
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"""Construct a dynamically-loading mapper property.
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This is essentially the same as
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using the ``lazy='dynamic'`` argument with :func:`relationship`::
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dynamic_loader(SomeClass)
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# is the same as
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relationship(SomeClass, lazy="dynamic")
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See the section :ref:`dynamic_relationship` for more details
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on dynamic loading.
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"""
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kw['lazy'] = 'dynamic'
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return relationship(argument, **kw)
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column_property = public_factory(ColumnProperty, ".orm.column_property")
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composite = public_factory(CompositeProperty, ".orm.composite")
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def backref(name, **kwargs):
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"""Create a back reference with explicit keyword arguments, which are the
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same arguments one can send to :func:`relationship`.
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Used with the ``backref`` keyword argument to :func:`relationship` in
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place of a string argument, e.g.::
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'items':relationship(SomeItem, backref=backref('parent', lazy='subquery'))
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"""
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return (name, kwargs)
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def deferred(*columns, **kw):
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"""Indicate a column-based mapped attribute that by default will
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not load unless accessed.
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:param \*columns: columns to be mapped. This is typically a single
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:class:`.Column` object, however a collection is supported in order
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to support multiple columns mapped under the same attribute.
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:param \**kw: additional keyword arguments passed to :class:`.ColumnProperty`.
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.. seealso::
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:ref:`deferred`
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"""
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return ColumnProperty(deferred=True, *columns, **kw)
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mapper = public_factory(Mapper, ".orm.mapper")
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synonym = public_factory(SynonymProperty, ".orm.synonym")
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comparable_property = public_factory(ComparableProperty,
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".orm.comparable_property")
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@_sa_util.deprecated("0.7", message=":func:`.compile_mappers` "
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"is renamed to :func:`.configure_mappers`")
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def compile_mappers():
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"""Initialize the inter-mapper relationships of all mappers that have
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been defined.
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"""
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configure_mappers()
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def clear_mappers():
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"""Remove all mappers from all classes.
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This function removes all instrumentation from classes and disposes
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of their associated mappers. Once called, the classes are unmapped
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and can be later re-mapped with new mappers.
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:func:`.clear_mappers` is *not* for normal use, as there is literally no
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valid usage for it outside of very specific testing scenarios. Normally,
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mappers are permanent structural components of user-defined classes, and
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are never discarded independently of their class. If a mapped class itself
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is garbage collected, its mapper is automatically disposed of as well. As
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such, :func:`.clear_mappers` is only for usage in test suites that re-use
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the same classes with different mappings, which is itself an extremely rare
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use case - the only such use case is in fact SQLAlchemy's own test suite,
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and possibly the test suites of other ORM extension libraries which
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intend to test various combinations of mapper construction upon a fixed
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set of classes.
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"""
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mapperlib._CONFIGURE_MUTEX.acquire()
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try:
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while _mapper_registry:
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try:
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# can't even reliably call list(weakdict) in jython
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mapper, b = _mapper_registry.popitem()
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mapper.dispose()
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except KeyError:
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pass
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finally:
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mapperlib._CONFIGURE_MUTEX.release()
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from . import strategy_options
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joinedload = strategy_options.joinedload._unbound_fn
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joinedload_all = strategy_options.joinedload._unbound_all_fn
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contains_eager = strategy_options.contains_eager._unbound_fn
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defer = strategy_options.defer._unbound_fn
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undefer = strategy_options.undefer._unbound_fn
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undefer_group = strategy_options.undefer_group._unbound_fn
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load_only = strategy_options.load_only._unbound_fn
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lazyload = strategy_options.lazyload._unbound_fn
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lazyload_all = strategy_options.lazyload_all._unbound_all_fn
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subqueryload = strategy_options.subqueryload._unbound_fn
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subqueryload_all = strategy_options.subqueryload_all._unbound_all_fn
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immediateload = strategy_options.immediateload._unbound_fn
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noload = strategy_options.noload._unbound_fn
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defaultload = strategy_options.defaultload._unbound_fn
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from .strategy_options import Load
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def eagerload(*args, **kwargs):
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"""A synonym for :func:`joinedload()`."""
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return joinedload(*args, **kwargs)
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def eagerload_all(*args, **kwargs):
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"""A synonym for :func:`joinedload_all()`"""
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return joinedload_all(*args, **kwargs)
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contains_alias = public_factory(AliasOption, ".orm.contains_alias")
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def __go(lcls):
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global __all__
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from .. import util as sa_util
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from . import dynamic
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from . import events
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import inspect as _inspect
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__all__ = sorted(name for name, obj in lcls.items()
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if not (name.startswith('_') or _inspect.ismodule(obj)))
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_sa_util.dependencies.resolve_all("sqlalchemy.orm")
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__go(locals())
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