# orm/__init__.py # Copyright (C) 2005-2017 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 """ 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 from .mapper import ( Mapper, _mapper_registry, class_mapper, configure_mappers, reconstructor, validates ) from .interfaces import ( EXT_CONTINUE, EXT_STOP, PropComparator, ) from .deprecated_interfaces import ( MapperExtension, SessionExtension, AttributeExtension, ) from .util import ( aliased, join, object_mapper, outerjoin, polymorphic_union, was_deleted, with_parent, with_polymorphic, ) from .properties import ColumnProperty from .relationships import RelationshipProperty from .descriptor_props import ( ComparableProperty, CompositeProperty, SynonymProperty, ) from .relationships import ( foreign, remote, ) from .session import ( Session, object_session, sessionmaker, make_transient, make_transient_to_detached ) from .scoping import ( scoped_session ) from . import mapper as mapperlib from .query import AliasOption, Query, Bundle from ..util.langhelpers import public_factory from .. import util as _sa_util from . import strategies as _strategies 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:`.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) 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 renamed to :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() from . import strategy_options 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 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 immediateload = strategy_options.immediateload._unbound_fn noload = strategy_options.noload._unbound_fn raiseload = strategy_options.raiseload._unbound_fn defaultload = strategy_options.defaultload._unbound_fn from .strategy_options import Load 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 from . import dynamic from . import events 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") __go(locals())