# orm/__init__.py
# Copyright (C) 2005-2020 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
Functional constructs for ORM configuration.
See the SQLAlchemy object relational tutorial and mapper configuration
documentation for an overview of how this module is used.
"""
from . import exc # noqa
from . import mapper as mapperlib # noqa
from . import strategy_options
from .deprecated_interfaces import AttributeExtension # noqa
from .deprecated_interfaces import MapperExtension # noqa
from .deprecated_interfaces import SessionExtension # noqa
from .descriptor_props import ComparableProperty # noqa
from .descriptor_props import CompositeProperty # noqa
from .descriptor_props import SynonymProperty # noqa
from .interfaces import EXT_CONTINUE # noqa
from .interfaces import EXT_SKIP # noqa
from .interfaces import EXT_STOP # noqa
from .interfaces import PropComparator # noqa
from .mapper import _mapper_registry
from .mapper import class_mapper # noqa
from .mapper import configure_mappers # noqa
from .mapper import Mapper # noqa
from .mapper import reconstructor # noqa
from .mapper import validates # noqa
from .properties import ColumnProperty # noqa
from .query import AliasOption # noqa
from .query import Bundle # noqa
from .query import Query # noqa
from .relationships import foreign # noqa
from .relationships import RelationshipProperty # noqa
from .relationships import remote # noqa
from .scoping import scoped_session # noqa
from .session import close_all_sessions # noqa
from .session import make_transient # noqa
from .session import make_transient_to_detached # noqa
from .session import object_session # noqa
from .session import Session # noqa
from .session import sessionmaker # noqa
from .strategy_options import Load # noqa
from .util import aliased # noqa
from .util import join # noqa
from .util import object_mapper # noqa
from .util import outerjoin # noqa
from .util import polymorphic_union # noqa
from .util import was_deleted # noqa
from .util import with_parent # noqa
from .util import with_polymorphic # noqa
from .. import sql as _sql
from .. import util as _sa_util
from ..util.langhelpers import public_factory
def create_session(bind=None, **kwargs):
r"""Create a new :class:`.Session`
with no automation enabled by default.
This function is used primarily for testing. The usual
route to :class:`.Session` creation is via its constructor
or the :func:`.sessionmaker` function.
:param bind: optional, a single Connectable to use for all
database access in the created
:class:`~sqlalchemy.orm.session.Session`.
:param \*\*kwargs: optional, passed through to the
:class:`.Session` constructor.
:returns: an :class:`~sqlalchemy.orm.session.Session` instance
The defaults of create_session() are the opposite of that of
:func:`sessionmaker`; ``autoflush`` and ``expire_on_commit`` are
False, ``autocommit`` is True. In this sense the session acts
more like the "classic" SQLAlchemy 0.3 session with these.
Usage::
>>> from sqlalchemy.orm import create_session
>>> session = create_session()
It is recommended to use :func:`sessionmaker` instead of
create_session().
"""
kwargs.setdefault("autoflush", False)
kwargs.setdefault("autocommit", True)
kwargs.setdefault("expire_on_commit", False)
return Session(bind=bind, **kwargs)
relationship = public_factory(RelationshipProperty, ".orm.relationship")
def relation(*arg, **kw):
"""A synonym for :func:`relationship`."""
return relationship(*arg, **kw)
def dynamic_loader(argument, **kw):
"""Construct a dynamically-loading mapper property.
This is essentially the same as
using the ``lazy='dynamic'`` argument with :func:`relationship`::
dynamic_loader(SomeClass)
# is the same as
relationship(SomeClass, lazy="dynamic")
See the section :ref:`dynamic_relationship` for more details
on dynamic loading.
"""
kw["lazy"] = "dynamic"
return relationship(argument, **kw)
column_property = public_factory(ColumnProperty, ".orm.column_property")
composite = public_factory(CompositeProperty, ".orm.composite")
def backref(name, **kwargs):
"""Create a back reference with explicit keyword arguments, which are the
same arguments one can send to :func:`relationship`.
Used with the ``backref`` keyword argument to :func:`relationship` in
place of a string argument, e.g.::
'items':relationship(
SomeItem, backref=backref('parent', lazy='subquery'))
.. seealso::
:ref:`relationships_backref`
"""
return (name, kwargs)
def deferred(*columns, **kw):
r"""Indicate a column-based mapped attribute that by default will
not load unless accessed.
:param \*columns: columns to be mapped. This is typically a single
:class:`_schema.Column` object,
however a collection is supported in order
to support multiple columns mapped under the same attribute.
:param \**kw: additional keyword arguments passed to
:class:`.ColumnProperty`.
.. seealso::
:ref:`deferred`
"""
return ColumnProperty(deferred=True, *columns, **kw)
def query_expression(default_expr=_sql.null()):
"""Indicate an attribute that populates from a query-time SQL expression.
:param default_expr: Optional SQL expression object that will be used in
all cases if not assigned later with :func:`_orm.with_expression`.
E.g.::
from sqlalchemy.sql import literal
class C(Base):
#...
my_expr = query_expression(literal(1))
.. versionadded:: 1.3.18
.. versionadded:: 1.2
.. seealso::
:ref:`mapper_querytime_expression`
"""
prop = ColumnProperty(default_expr)
prop.strategy_key = (("query_expression", True),)
return prop
mapper = public_factory(Mapper, ".orm.mapper")
synonym = public_factory(SynonymProperty, ".orm.synonym")
comparable_property = public_factory(
ComparableProperty, ".orm.comparable_property"
)
@_sa_util.deprecated(
"0.7",
message=":func:`.compile_mappers` is deprecated and will be removed "
"in a future release. Please use :func:`.configure_mappers`",
)
def compile_mappers():
"""Initialize the inter-mapper relationships of all mappers that have
been defined.
"""
configure_mappers()
def clear_mappers():
"""Remove all mappers from all classes.
This function removes all instrumentation from classes and disposes
of their associated mappers. Once called, the classes are unmapped
and can be later re-mapped with new mappers.
:func:`.clear_mappers` is *not* for normal use, as there is literally no
valid usage for it outside of very specific testing scenarios. Normally,
mappers are permanent structural components of user-defined classes, and
are never discarded independently of their class. If a mapped class
itself is garbage collected, its mapper is automatically disposed of as
well. As such, :func:`.clear_mappers` is only for usage in test suites
that re-use the same classes with different mappings, which is itself an
extremely rare use case - the only such use case is in fact SQLAlchemy's
own test suite, and possibly the test suites of other ORM extension
libraries which intend to test various combinations of mapper construction
upon a fixed set of classes.
"""
mapperlib._CONFIGURE_MUTEX.acquire()
try:
while _mapper_registry:
try:
# can't even reliably call list(weakdict) in jython
mapper, b = _mapper_registry.popitem()
mapper.dispose()
except KeyError:
pass
finally:
mapperlib._CONFIGURE_MUTEX.release()
joinedload = strategy_options.joinedload._unbound_fn
joinedload_all = strategy_options.joinedload._unbound_all_fn
contains_eager = strategy_options.contains_eager._unbound_fn
defer = strategy_options.defer._unbound_fn
undefer = strategy_options.undefer._unbound_fn
undefer_group = strategy_options.undefer_group._unbound_fn
with_expression = strategy_options.with_expression._unbound_fn
load_only = strategy_options.load_only._unbound_fn
lazyload = strategy_options.lazyload._unbound_fn
lazyload_all = strategy_options.lazyload_all._unbound_all_fn
subqueryload = strategy_options.subqueryload._unbound_fn
subqueryload_all = strategy_options.subqueryload_all._unbound_all_fn
selectinload = strategy_options.selectinload._unbound_fn
selectinload_all = strategy_options.selectinload_all._unbound_all_fn
immediateload = strategy_options.immediateload._unbound_fn
noload = strategy_options.noload._unbound_fn
raiseload = strategy_options.raiseload._unbound_fn
defaultload = strategy_options.defaultload._unbound_fn
selectin_polymorphic = strategy_options.selectin_polymorphic._unbound_fn
def eagerload(*args, **kwargs):
"""A synonym for :func:`joinedload()`."""
return joinedload(*args, **kwargs)
def eagerload_all(*args, **kwargs):
"""A synonym for :func:`joinedload_all()`"""
return joinedload_all(*args, **kwargs)
contains_alias = public_factory(AliasOption, ".orm.contains_alias")
def __go(lcls):
global __all__
from .. import util as sa_util # noqa
from . import dynamic # noqa
from . import events # noqa
from . import loading # noqa
import inspect as _inspect
__all__ = sorted(
name
for name, obj in lcls.items()
if not (name.startswith("_") or _inspect.ismodule(obj))
)
_sa_util.dependencies.resolve_all("sqlalchemy.orm")
_sa_util.dependencies.resolve_all("sqlalchemy.ext")
__go(locals())