3261 lines
122 KiB
Python
3261 lines
122 KiB
Python
# orm/relationships.py
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# Copyright (C) 2005-2019 the SQLAlchemy authors and contributors
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# <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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"""Heuristics related to join conditions as used in
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:func:`.relationship`.
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Provides the :class:`.JoinCondition` object, which encapsulates
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SQL annotation and aliasing behavior focused on the `primaryjoin`
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and `secondaryjoin` aspects of :func:`.relationship`.
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"""
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from __future__ import absolute_import
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import collections
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import weakref
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from . import attributes
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from . import dependency
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from . import mapper as mapperlib
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from .base import state_str
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from .interfaces import MANYTOMANY
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from .interfaces import MANYTOONE
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from .interfaces import ONETOMANY
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from .interfaces import PropComparator
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from .interfaces import StrategizedProperty
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from .util import _orm_annotate
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from .util import _orm_deannotate
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from .util import CascadeOptions
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from .. import exc as sa_exc
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from .. import log
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from .. import schema
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from .. import sql
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from .. import util
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from ..inspection import inspect
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from ..sql import expression
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from ..sql import operators
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from ..sql import visitors
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from ..sql.util import _deep_deannotate
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from ..sql.util import _shallow_annotate
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from ..sql.util import adapt_criterion_to_null
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from ..sql.util import ClauseAdapter
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from ..sql.util import join_condition
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from ..sql.util import selectables_overlap
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from ..sql.util import visit_binary_product
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def remote(expr):
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"""Annotate a portion of a primaryjoin expression
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with a 'remote' annotation.
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See the section :ref:`relationship_custom_foreign` for a
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description of use.
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.. seealso::
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:ref:`relationship_custom_foreign`
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:func:`.foreign`
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"""
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return _annotate_columns(
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expression._clause_element_as_expr(expr), {"remote": True}
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)
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def foreign(expr):
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"""Annotate a portion of a primaryjoin expression
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with a 'foreign' annotation.
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See the section :ref:`relationship_custom_foreign` for a
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description of use.
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.. seealso::
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:ref:`relationship_custom_foreign`
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:func:`.remote`
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"""
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return _annotate_columns(
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expression._clause_element_as_expr(expr), {"foreign": True}
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)
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@log.class_logger
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@util.langhelpers.dependency_for("sqlalchemy.orm.properties", add_to_all=True)
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class RelationshipProperty(StrategizedProperty):
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"""Describes an object property that holds a single item or list
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of items that correspond to a related database table.
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Public constructor is the :func:`.orm.relationship` function.
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.. seealso::
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:ref:`relationship_config_toplevel`
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"""
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strategy_wildcard_key = "relationship"
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_dependency_processor = None
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@util.deprecated_params(
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extension=(
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"0.7",
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":class:`.AttributeExtension` is deprecated in favor of the "
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":class:`.AttributeEvents` listener interface. The "
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":paramref:`.relationship.extension` parameter will be "
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"removed in a future release.",
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)
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)
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def __init__(
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self,
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argument,
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secondary=None,
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primaryjoin=None,
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secondaryjoin=None,
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foreign_keys=None,
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uselist=None,
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order_by=False,
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backref=None,
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back_populates=None,
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post_update=False,
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cascade=False,
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extension=None,
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viewonly=False,
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lazy="select",
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collection_class=None,
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passive_deletes=False,
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passive_updates=True,
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remote_side=None,
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enable_typechecks=True,
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join_depth=None,
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comparator_factory=None,
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single_parent=False,
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innerjoin=False,
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distinct_target_key=None,
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doc=None,
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active_history=False,
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cascade_backrefs=True,
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load_on_pending=False,
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bake_queries=True,
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_local_remote_pairs=None,
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query_class=None,
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info=None,
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omit_join=None,
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):
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"""Provide a relationship between two mapped classes.
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This corresponds to a parent-child or associative table relationship.
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The constructed class is an instance of
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:class:`.RelationshipProperty`.
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A typical :func:`.relationship`, used in a classical mapping::
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mapper(Parent, properties={
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'children': relationship(Child)
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})
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Some arguments accepted by :func:`.relationship` optionally accept a
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callable function, which when called produces the desired value.
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The callable is invoked by the parent :class:`.Mapper` at "mapper
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initialization" time, which happens only when mappers are first used,
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and is assumed to be after all mappings have been constructed. This
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can be used to resolve order-of-declaration and other dependency
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issues, such as if ``Child`` is declared below ``Parent`` in the same
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file::
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mapper(Parent, properties={
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"children":relationship(lambda: Child,
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order_by=lambda: Child.id)
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})
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When using the :ref:`declarative_toplevel` extension, the Declarative
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initializer allows string arguments to be passed to
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:func:`.relationship`. These string arguments are converted into
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callables that evaluate the string as Python code, using the
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Declarative class-registry as a namespace. This allows the lookup of
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related classes to be automatic via their string name, and removes the
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need for related classes to be imported into the local module space
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before the dependent classes have been declared. It is still required
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that the modules in which these related classes appear are imported
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anywhere in the application at some point before the related mappings
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are actually used, else a lookup error will be raised when the
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:func:`.relationship` attempts to resolve the string reference to the
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related class. An example of a string- resolved class is as
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follows::
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from sqlalchemy.ext.declarative import declarative_base
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Base = declarative_base()
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class Parent(Base):
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__tablename__ = 'parent'
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id = Column(Integer, primary_key=True)
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children = relationship("Child", order_by="Child.id")
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.. seealso::
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:ref:`relationship_config_toplevel` - Full introductory and
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reference documentation for :func:`.relationship`.
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:ref:`orm_tutorial_relationship` - ORM tutorial introduction.
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:param argument:
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a mapped class, or actual :class:`.Mapper` instance, representing
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the target of the relationship.
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:paramref:`~.relationship.argument` may also be passed as a callable
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function which is evaluated at mapper initialization time, and may
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be passed as a Python-evaluable string when using Declarative.
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.. seealso::
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:ref:`declarative_configuring_relationships` - further detail
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on relationship configuration when using Declarative.
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:param secondary:
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for a many-to-many relationship, specifies the intermediary
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table, and is typically an instance of :class:`.Table`.
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In less common circumstances, the argument may also be specified
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as an :class:`.Alias` construct, or even a :class:`.Join` construct.
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:paramref:`~.relationship.secondary` may
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also be passed as a callable function which is evaluated at
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mapper initialization time. When using Declarative, it may also
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be a string argument noting the name of a :class:`.Table` that is
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present in the :class:`.MetaData` collection associated with the
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parent-mapped :class:`.Table`.
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The :paramref:`~.relationship.secondary` keyword argument is
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typically applied in the case where the intermediary :class:`.Table`
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is not otherwise expressed in any direct class mapping. If the
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"secondary" table is also explicitly mapped elsewhere (e.g. as in
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:ref:`association_pattern`), one should consider applying the
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:paramref:`~.relationship.viewonly` flag so that this
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:func:`.relationship` is not used for persistence operations which
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may conflict with those of the association object pattern.
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.. seealso::
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:ref:`relationships_many_to_many` - Reference example of "many
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to many".
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:ref:`orm_tutorial_many_to_many` - ORM tutorial introduction to
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many-to-many relationships.
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:ref:`self_referential_many_to_many` - Specifics on using
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many-to-many in a self-referential case.
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:ref:`declarative_many_to_many` - Additional options when using
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Declarative.
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:ref:`association_pattern` - an alternative to
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:paramref:`~.relationship.secondary` when composing association
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table relationships, allowing additional attributes to be
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specified on the association table.
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:ref:`composite_secondary_join` - a lesser-used pattern which
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in some cases can enable complex :func:`.relationship` SQL
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conditions to be used.
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.. versionadded:: 0.9.2 :paramref:`~.relationship.secondary` works
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more effectively when referring to a :class:`.Join` instance.
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:param active_history=False:
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When ``True``, indicates that the "previous" value for a
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many-to-one reference should be loaded when replaced, if
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not already loaded. Normally, history tracking logic for
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simple many-to-ones only needs to be aware of the "new"
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value in order to perform a flush. This flag is available
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for applications that make use of
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:func:`.attributes.get_history` which also need to know
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the "previous" value of the attribute.
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:param backref:
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indicates the string name of a property to be placed on the related
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mapper's class that will handle this relationship in the other
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direction. The other property will be created automatically
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when the mappers are configured. Can also be passed as a
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:func:`.backref` object to control the configuration of the
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new relationship.
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.. seealso::
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:ref:`relationships_backref` - Introductory documentation and
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examples.
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:paramref:`~.relationship.back_populates` - alternative form
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of backref specification.
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:func:`.backref` - allows control over :func:`.relationship`
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configuration when using :paramref:`~.relationship.backref`.
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:param back_populates:
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Takes a string name and has the same meaning as
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:paramref:`~.relationship.backref`, except the complementing
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property is **not** created automatically, and instead must be
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configured explicitly on the other mapper. The complementing
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property should also indicate
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:paramref:`~.relationship.back_populates` to this relationship to
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ensure proper functioning.
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.. seealso::
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:ref:`relationships_backref` - Introductory documentation and
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examples.
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:paramref:`~.relationship.backref` - alternative form
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of backref specification.
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:param bake_queries=True:
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Use the :class:`.BakedQuery` cache to cache the construction of SQL
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used in lazy loads. True by default. Set to False if the
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join condition of the relationship has unusual features that
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might not respond well to statement caching.
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.. versionchanged:: 1.2
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"Baked" loading is the default implementation for the "select",
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a.k.a. "lazy" loading strategy for relationships.
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.. versionadded:: 1.0.0
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.. seealso::
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:ref:`baked_toplevel`
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:param cascade:
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a comma-separated list of cascade rules which determines how
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Session operations should be "cascaded" from parent to child.
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This defaults to ``False``, which means the default cascade
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should be used - this default cascade is ``"save-update, merge"``.
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The available cascades are ``save-update``, ``merge``,
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``expunge``, ``delete``, ``delete-orphan``, and ``refresh-expire``.
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An additional option, ``all`` indicates shorthand for
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``"save-update, merge, refresh-expire,
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expunge, delete"``, and is often used as in ``"all, delete-orphan"``
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to indicate that related objects should follow along with the
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parent object in all cases, and be deleted when de-associated.
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.. seealso::
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:ref:`unitofwork_cascades` - Full detail on each of the available
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cascade options.
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:ref:`tutorial_delete_cascade` - Tutorial example describing
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a delete cascade.
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:param cascade_backrefs=True:
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a boolean value indicating if the ``save-update`` cascade should
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operate along an assignment event intercepted by a backref.
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When set to ``False``, the attribute managed by this relationship
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will not cascade an incoming transient object into the session of a
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persistent parent, if the event is received via backref.
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.. seealso::
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:ref:`backref_cascade` - Full discussion and examples on how
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the :paramref:`~.relationship.cascade_backrefs` option is used.
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:param collection_class:
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a class or callable that returns a new list-holding object. will
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be used in place of a plain list for storing elements.
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.. seealso::
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:ref:`custom_collections` - Introductory documentation and
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examples.
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:param comparator_factory:
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a class which extends :class:`.RelationshipProperty.Comparator`
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which provides custom SQL clause generation for comparison
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operations.
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.. seealso::
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:class:`.PropComparator` - some detail on redefining comparators
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at this level.
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:ref:`custom_comparators` - Brief intro to this feature.
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:param distinct_target_key=None:
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Indicate if a "subquery" eager load should apply the DISTINCT
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keyword to the innermost SELECT statement. When left as ``None``,
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the DISTINCT keyword will be applied in those cases when the target
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columns do not comprise the full primary key of the target table.
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When set to ``True``, the DISTINCT keyword is applied to the
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innermost SELECT unconditionally.
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It may be desirable to set this flag to False when the DISTINCT is
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reducing performance of the innermost subquery beyond that of what
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duplicate innermost rows may be causing.
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.. versionchanged:: 0.9.0 -
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:paramref:`~.relationship.distinct_target_key` now defaults to
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``None``, so that the feature enables itself automatically for
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those cases where the innermost query targets a non-unique
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key.
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.. seealso::
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:ref:`loading_toplevel` - includes an introduction to subquery
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eager loading.
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:param doc:
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docstring which will be applied to the resulting descriptor.
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:param extension:
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an :class:`.AttributeExtension` instance, or list of extensions,
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which will be prepended to the list of attribute listeners for
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the resulting descriptor placed on the class.
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:param foreign_keys:
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a list of columns which are to be used as "foreign key"
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columns, or columns which refer to the value in a remote
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column, within the context of this :func:`.relationship`
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object's :paramref:`~.relationship.primaryjoin` condition.
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That is, if the :paramref:`~.relationship.primaryjoin`
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condition of this :func:`.relationship` is ``a.id ==
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b.a_id``, and the values in ``b.a_id`` are required to be
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present in ``a.id``, then the "foreign key" column of this
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:func:`.relationship` is ``b.a_id``.
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In normal cases, the :paramref:`~.relationship.foreign_keys`
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parameter is **not required.** :func:`.relationship` will
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automatically determine which columns in the
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:paramref:`~.relationship.primaryjoin` condition are to be
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considered "foreign key" columns based on those
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:class:`.Column` objects that specify :class:`.ForeignKey`,
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or are otherwise listed as referencing columns in a
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:class:`.ForeignKeyConstraint` construct.
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:paramref:`~.relationship.foreign_keys` is only needed when:
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1. There is more than one way to construct a join from the local
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table to the remote table, as there are multiple foreign key
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references present. Setting ``foreign_keys`` will limit the
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:func:`.relationship` to consider just those columns specified
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here as "foreign".
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2. The :class:`.Table` being mapped does not actually have
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:class:`.ForeignKey` or :class:`.ForeignKeyConstraint`
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constructs present, often because the table
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was reflected from a database that does not support foreign key
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reflection (MySQL MyISAM).
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3. The :paramref:`~.relationship.primaryjoin` argument is used to
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construct a non-standard join condition, which makes use of
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columns or expressions that do not normally refer to their
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"parent" column, such as a join condition expressed by a
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complex comparison using a SQL function.
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The :func:`.relationship` construct will raise informative
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error messages that suggest the use of the
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:paramref:`~.relationship.foreign_keys` parameter when
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presented with an ambiguous condition. In typical cases,
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if :func:`.relationship` doesn't raise any exceptions, the
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:paramref:`~.relationship.foreign_keys` parameter is usually
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not needed.
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:paramref:`~.relationship.foreign_keys` may also be passed as a
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callable function which is evaluated at mapper initialization time,
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and may be passed as a Python-evaluable string when using
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Declarative.
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.. seealso::
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:ref:`relationship_foreign_keys`
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:ref:`relationship_custom_foreign`
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:func:`.foreign` - allows direct annotation of the "foreign"
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columns within a :paramref:`~.relationship.primaryjoin` condition.
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:param info: Optional data dictionary which will be populated into the
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:attr:`.MapperProperty.info` attribute of this object.
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:param innerjoin=False:
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when ``True``, joined eager loads will use an inner join to join
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against related tables instead of an outer join. The purpose
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of this option is generally one of performance, as inner joins
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generally perform better than outer joins.
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This flag can be set to ``True`` when the relationship references an
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object via many-to-one using local foreign keys that are not
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nullable, or when the reference is one-to-one or a collection that
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is guaranteed to have one or at least one entry.
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The option supports the same "nested" and "unnested" options as
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that of :paramref:`.joinedload.innerjoin`. See that flag
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for details on nested / unnested behaviors.
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.. seealso::
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:paramref:`.joinedload.innerjoin` - the option as specified by
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loader option, including detail on nesting behavior.
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:ref:`what_kind_of_loading` - Discussion of some details of
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various loader options.
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:param join_depth:
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when non-``None``, an integer value indicating how many levels
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deep "eager" loaders should join on a self-referring or cyclical
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relationship. The number counts how many times the same Mapper
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shall be present in the loading condition along a particular join
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branch. When left at its default of ``None``, eager loaders
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will stop chaining when they encounter a the same target mapper
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which is already higher up in the chain. This option applies
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both to joined- and subquery- eager loaders.
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.. seealso::
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:ref:`self_referential_eager_loading` - Introductory documentation
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and examples.
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:param lazy='select': specifies
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how the related items should be loaded. Default value is
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``select``. Values include:
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* ``select`` - items should be loaded lazily when the property is
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first accessed, using a separate SELECT statement, or identity map
|
|
fetch for simple many-to-one references.
|
|
|
|
* ``immediate`` - items should be loaded as the parents are loaded,
|
|
using a separate SELECT statement, or identity map fetch for
|
|
simple many-to-one references.
|
|
|
|
* ``joined`` - items should be loaded "eagerly" in the same query as
|
|
that of the parent, using a JOIN or LEFT OUTER JOIN. Whether
|
|
the join is "outer" or not is determined by the
|
|
:paramref:`~.relationship.innerjoin` parameter.
|
|
|
|
* ``subquery`` - items should be loaded "eagerly" as the parents are
|
|
loaded, using one additional SQL statement, which issues a JOIN to
|
|
a subquery of the original statement, for each collection
|
|
requested.
|
|
|
|
* ``selectin`` - items should be loaded "eagerly" as the parents
|
|
are loaded, using one or more additional SQL statements, which
|
|
issues a JOIN to the immediate parent object, specifying primary
|
|
key identifiers using an IN clause.
|
|
|
|
.. versionadded:: 1.2
|
|
|
|
* ``noload`` - no loading should occur at any time. This is to
|
|
support "write-only" attributes, or attributes which are
|
|
populated in some manner specific to the application.
|
|
|
|
* ``raise`` - lazy loading is disallowed; accessing
|
|
the attribute, if its value were not already loaded via eager
|
|
loading, will raise an :exc:`~sqlalchemy.exc.InvalidRequestError`.
|
|
This strategy can be used when objects are to be detached from
|
|
their attached :class:`.Session` after they are loaded.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
* ``raise_on_sql`` - lazy loading that emits SQL is disallowed;
|
|
accessing the attribute, if its value were not already loaded via
|
|
eager loading, will raise an
|
|
:exc:`~sqlalchemy.exc.InvalidRequestError`, **if the lazy load
|
|
needs to emit SQL**. If the lazy load can pull the related value
|
|
from the identity map or determine that it should be None, the
|
|
value is loaded. This strategy can be used when objects will
|
|
remain associated with the attached :class:`.Session`, however
|
|
additional SELECT statements should be blocked.
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
* ``dynamic`` - the attribute will return a pre-configured
|
|
:class:`.Query` object for all read
|
|
operations, onto which further filtering operations can be
|
|
applied before iterating the results. See
|
|
the section :ref:`dynamic_relationship` for more details.
|
|
|
|
* True - a synonym for 'select'
|
|
|
|
* False - a synonym for 'joined'
|
|
|
|
* None - a synonym for 'noload'
|
|
|
|
.. seealso::
|
|
|
|
:doc:`/orm/loading_relationships` - Full documentation on
|
|
relationship loader configuration.
|
|
|
|
:ref:`dynamic_relationship` - detail on the ``dynamic`` option.
|
|
|
|
:ref:`collections_noload_raiseload` - notes on "noload" and "raise"
|
|
|
|
:param load_on_pending=False:
|
|
Indicates loading behavior for transient or pending parent objects.
|
|
|
|
When set to ``True``, causes the lazy-loader to
|
|
issue a query for a parent object that is not persistent, meaning it
|
|
has never been flushed. This may take effect for a pending object
|
|
when autoflush is disabled, or for a transient object that has been
|
|
"attached" to a :class:`.Session` but is not part of its pending
|
|
collection.
|
|
|
|
The :paramref:`~.relationship.load_on_pending` flag does not improve
|
|
behavior when the ORM is used normally - object references should be
|
|
constructed at the object level, not at the foreign key level, so
|
|
that they are present in an ordinary way before a flush proceeds.
|
|
This flag is not not intended for general use.
|
|
|
|
.. seealso::
|
|
|
|
:meth:`.Session.enable_relationship_loading` - this method
|
|
establishes "load on pending" behavior for the whole object, and
|
|
also allows loading on objects that remain transient or
|
|
detached.
|
|
|
|
:param order_by:
|
|
indicates the ordering that should be applied when loading these
|
|
items. :paramref:`~.relationship.order_by` is expected to refer to
|
|
one of the :class:`.Column` objects to which the target class is
|
|
mapped, or the attribute itself bound to the target class which
|
|
refers to the column.
|
|
|
|
:paramref:`~.relationship.order_by` may also be passed as a callable
|
|
function which is evaluated at mapper initialization time, and may
|
|
be passed as a Python-evaluable string when using Declarative.
|
|
|
|
:param passive_deletes=False:
|
|
Indicates loading behavior during delete operations.
|
|
|
|
A value of True indicates that unloaded child items should not
|
|
be loaded during a delete operation on the parent. Normally,
|
|
when a parent item is deleted, all child items are loaded so
|
|
that they can either be marked as deleted, or have their
|
|
foreign key to the parent set to NULL. Marking this flag as
|
|
True usually implies an ON DELETE <CASCADE|SET NULL> rule is in
|
|
place which will handle updating/deleting child rows on the
|
|
database side.
|
|
|
|
Additionally, setting the flag to the string value 'all' will
|
|
disable the "nulling out" of the child foreign keys, when the parent
|
|
object is deleted and there is no delete or delete-orphan cascade
|
|
enabled. This is typically used when a triggering or error raise
|
|
scenario is in place on the database side. Note that the foreign
|
|
key attributes on in-session child objects will not be changed after
|
|
a flush occurs so this is a very special use-case setting.
|
|
Additionally, the "nulling out" will still occur if the child
|
|
object is de-associated with the parent.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`passive_deletes` - Introductory documentation
|
|
and examples.
|
|
|
|
:param passive_updates=True:
|
|
Indicates the persistence behavior to take when a referenced
|
|
primary key value changes in place, indicating that the referencing
|
|
foreign key columns will also need their value changed.
|
|
|
|
When True, it is assumed that ``ON UPDATE CASCADE`` is configured on
|
|
the foreign key in the database, and that the database will
|
|
handle propagation of an UPDATE from a source column to
|
|
dependent rows. When False, the SQLAlchemy :func:`.relationship`
|
|
construct will attempt to emit its own UPDATE statements to
|
|
modify related targets. However note that SQLAlchemy **cannot**
|
|
emit an UPDATE for more than one level of cascade. Also,
|
|
setting this flag to False is not compatible in the case where
|
|
the database is in fact enforcing referential integrity, unless
|
|
those constraints are explicitly "deferred", if the target backend
|
|
supports it.
|
|
|
|
It is highly advised that an application which is employing
|
|
mutable primary keys keeps ``passive_updates`` set to True,
|
|
and instead uses the referential integrity features of the database
|
|
itself in order to handle the change efficiently and fully.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`passive_updates` - Introductory documentation and
|
|
examples.
|
|
|
|
:paramref:`.mapper.passive_updates` - a similar flag which
|
|
takes effect for joined-table inheritance mappings.
|
|
|
|
:param post_update:
|
|
this indicates that the relationship should be handled by a
|
|
second UPDATE statement after an INSERT or before a
|
|
DELETE. Currently, it also will issue an UPDATE after the
|
|
instance was UPDATEd as well, although this technically should
|
|
be improved. This flag is used to handle saving bi-directional
|
|
dependencies between two individual rows (i.e. each row
|
|
references the other), where it would otherwise be impossible to
|
|
INSERT or DELETE both rows fully since one row exists before the
|
|
other. Use this flag when a particular mapping arrangement will
|
|
incur two rows that are dependent on each other, such as a table
|
|
that has a one-to-many relationship to a set of child rows, and
|
|
also has a column that references a single child row within that
|
|
list (i.e. both tables contain a foreign key to each other). If
|
|
a flush operation returns an error that a "cyclical
|
|
dependency" was detected, this is a cue that you might want to
|
|
use :paramref:`~.relationship.post_update` to "break" the cycle.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`post_update` - Introductory documentation and examples.
|
|
|
|
:param primaryjoin:
|
|
a SQL expression that will be used as the primary
|
|
join of the child object against the parent object, or in a
|
|
many-to-many relationship the join of the parent object to the
|
|
association table. By default, this value is computed based on the
|
|
foreign key relationships of the parent and child tables (or
|
|
association table).
|
|
|
|
:paramref:`~.relationship.primaryjoin` may also be passed as a
|
|
callable function which is evaluated at mapper initialization time,
|
|
and may be passed as a Python-evaluable string when using
|
|
Declarative.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`relationship_primaryjoin`
|
|
|
|
:param remote_side:
|
|
used for self-referential relationships, indicates the column or
|
|
list of columns that form the "remote side" of the relationship.
|
|
|
|
:paramref:`.relationship.remote_side` may also be passed as a
|
|
callable function which is evaluated at mapper initialization time,
|
|
and may be passed as a Python-evaluable string when using
|
|
Declarative.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`self_referential` - in-depth explanation of how
|
|
:paramref:`~.relationship.remote_side`
|
|
is used to configure self-referential relationships.
|
|
|
|
:func:`.remote` - an annotation function that accomplishes the
|
|
same purpose as :paramref:`~.relationship.remote_side`, typically
|
|
when a custom :paramref:`~.relationship.primaryjoin` condition
|
|
is used.
|
|
|
|
:param query_class:
|
|
a :class:`.Query` subclass that will be used as the base of the
|
|
"appender query" returned by a "dynamic" relationship, that
|
|
is, a relationship that specifies ``lazy="dynamic"`` or was
|
|
otherwise constructed using the :func:`.orm.dynamic_loader`
|
|
function.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`dynamic_relationship` - Introduction to "dynamic"
|
|
relationship loaders.
|
|
|
|
:param secondaryjoin:
|
|
a SQL expression that will be used as the join of
|
|
an association table to the child object. By default, this value is
|
|
computed based on the foreign key relationships of the association
|
|
and child tables.
|
|
|
|
:paramref:`~.relationship.secondaryjoin` may also be passed as a
|
|
callable function which is evaluated at mapper initialization time,
|
|
and may be passed as a Python-evaluable string when using
|
|
Declarative.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`relationship_primaryjoin`
|
|
|
|
:param single_parent:
|
|
when True, installs a validator which will prevent objects
|
|
from being associated with more than one parent at a time.
|
|
This is used for many-to-one or many-to-many relationships that
|
|
should be treated either as one-to-one or one-to-many. Its usage
|
|
is optional, except for :func:`.relationship` constructs which
|
|
are many-to-one or many-to-many and also
|
|
specify the ``delete-orphan`` cascade option. The
|
|
:func:`.relationship` construct itself will raise an error
|
|
instructing when this option is required.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`unitofwork_cascades` - includes detail on when the
|
|
:paramref:`~.relationship.single_parent` flag may be appropriate.
|
|
|
|
:param uselist:
|
|
a boolean that indicates if this property should be loaded as a
|
|
list or a scalar. In most cases, this value is determined
|
|
automatically by :func:`.relationship` at mapper configuration
|
|
time, based on the type and direction
|
|
of the relationship - one to many forms a list, many to one
|
|
forms a scalar, many to many is a list. If a scalar is desired
|
|
where normally a list would be present, such as a bi-directional
|
|
one-to-one relationship, set :paramref:`~.relationship.uselist` to
|
|
False.
|
|
|
|
The :paramref:`~.relationship.uselist` flag is also available on an
|
|
existing :func:`.relationship` construct as a read-only attribute,
|
|
which can be used to determine if this :func:`.relationship` deals
|
|
with collections or scalar attributes::
|
|
|
|
>>> User.addresses.property.uselist
|
|
True
|
|
|
|
.. seealso::
|
|
|
|
:ref:`relationships_one_to_one` - Introduction to the "one to
|
|
one" relationship pattern, which is typically when the
|
|
:paramref:`~.relationship.uselist` flag is needed.
|
|
|
|
:param viewonly=False:
|
|
when set to True, the relationship is used only for loading objects,
|
|
and not for any persistence operation. A :func:`.relationship`
|
|
which specifies :paramref:`~.relationship.viewonly` can work
|
|
with a wider range of SQL operations within the
|
|
:paramref:`~.relationship.primaryjoin` condition, including
|
|
operations that feature the use of a variety of comparison operators
|
|
as well as SQL functions such as :func:`~.sql.expression.cast`. The
|
|
:paramref:`~.relationship.viewonly` flag is also of general use when
|
|
defining any kind of :func:`~.relationship` that doesn't represent
|
|
the full set of related objects, to prevent modifications of the
|
|
collection from resulting in persistence operations.
|
|
|
|
:param omit_join:
|
|
Allows manual control over the "selectin" automatic join
|
|
optimization. Set to ``False`` to disable the "omit join" feature
|
|
added in SQLAlchemy 1.3; or leave as ``None`` to leave automatic
|
|
optimization in place.
|
|
|
|
.. note:: This flag may only be set to ``False``. It is not
|
|
necessary to set it to ``True`` as the "omit_join" optimization is
|
|
automatically detected; if it is not detected, then the
|
|
optimization is not supported.
|
|
|
|
.. versionchanged:: 1.3.11 setting ``omit_join`` to True will now
|
|
emit a warning as this was not the intended use of this flag.
|
|
|
|
.. versionadded:: 1.3
|
|
|
|
|
|
"""
|
|
super(RelationshipProperty, self).__init__()
|
|
|
|
self.uselist = uselist
|
|
self.argument = argument
|
|
self.secondary = secondary
|
|
self.primaryjoin = primaryjoin
|
|
self.secondaryjoin = secondaryjoin
|
|
self.post_update = post_update
|
|
self.direction = None
|
|
self.viewonly = viewonly
|
|
self.lazy = lazy
|
|
self.single_parent = single_parent
|
|
self._user_defined_foreign_keys = foreign_keys
|
|
self.collection_class = collection_class
|
|
self.passive_deletes = passive_deletes
|
|
self.cascade_backrefs = cascade_backrefs
|
|
self.passive_updates = passive_updates
|
|
self.remote_side = remote_side
|
|
self.enable_typechecks = enable_typechecks
|
|
self.query_class = query_class
|
|
self.innerjoin = innerjoin
|
|
self.distinct_target_key = distinct_target_key
|
|
self.doc = doc
|
|
self.active_history = active_history
|
|
self.join_depth = join_depth
|
|
if omit_join:
|
|
util.warn(
|
|
"setting omit_join to True is not supported; selectin "
|
|
"loading of this relationship may not work correctly if this "
|
|
"flag is set explicitly. omit_join optimization is "
|
|
"automatically detected for conditions under which it is "
|
|
"supported."
|
|
)
|
|
|
|
self.omit_join = omit_join
|
|
self.local_remote_pairs = _local_remote_pairs
|
|
self.extension = extension
|
|
self.bake_queries = bake_queries
|
|
self.load_on_pending = load_on_pending
|
|
self.comparator_factory = (
|
|
comparator_factory or RelationshipProperty.Comparator
|
|
)
|
|
self.comparator = self.comparator_factory(self, None)
|
|
util.set_creation_order(self)
|
|
|
|
if info is not None:
|
|
self.info = info
|
|
|
|
self.strategy_key = (("lazy", self.lazy),)
|
|
|
|
self._reverse_property = set()
|
|
|
|
self.cascade = (
|
|
cascade if cascade is not False else "save-update, merge"
|
|
)
|
|
|
|
self.order_by = order_by
|
|
|
|
self.back_populates = back_populates
|
|
|
|
if self.back_populates:
|
|
if backref:
|
|
raise sa_exc.ArgumentError(
|
|
"backref and back_populates keyword arguments "
|
|
"are mutually exclusive"
|
|
)
|
|
self.backref = None
|
|
else:
|
|
self.backref = backref
|
|
|
|
def instrument_class(self, mapper):
|
|
attributes.register_descriptor(
|
|
mapper.class_,
|
|
self.key,
|
|
comparator=self.comparator_factory(self, mapper),
|
|
parententity=mapper,
|
|
doc=self.doc,
|
|
)
|
|
|
|
class Comparator(PropComparator):
|
|
"""Produce boolean, comparison, and other operators for
|
|
:class:`.RelationshipProperty` attributes.
|
|
|
|
See the documentation for :class:`.PropComparator` for a brief
|
|
overview of ORM level operator definition.
|
|
|
|
.. seealso::
|
|
|
|
:class:`.PropComparator`
|
|
|
|
:class:`.ColumnProperty.Comparator`
|
|
|
|
:class:`.ColumnOperators`
|
|
|
|
:ref:`types_operators`
|
|
|
|
:attr:`.TypeEngine.comparator_factory`
|
|
|
|
"""
|
|
|
|
_of_type = None
|
|
|
|
def __init__(
|
|
self, prop, parentmapper, adapt_to_entity=None, of_type=None
|
|
):
|
|
"""Construction of :class:`.RelationshipProperty.Comparator`
|
|
is internal to the ORM's attribute mechanics.
|
|
|
|
"""
|
|
self.prop = prop
|
|
self._parententity = parentmapper
|
|
self._adapt_to_entity = adapt_to_entity
|
|
if of_type:
|
|
self._of_type = of_type
|
|
|
|
def adapt_to_entity(self, adapt_to_entity):
|
|
return self.__class__(
|
|
self.property,
|
|
self._parententity,
|
|
adapt_to_entity=adapt_to_entity,
|
|
of_type=self._of_type,
|
|
)
|
|
|
|
@util.memoized_property
|
|
def entity(self):
|
|
"""The target entity referred to by this
|
|
:class:`.RelationshipProperty.Comparator`.
|
|
|
|
This is either a :class:`.Mapper` or :class:`.AliasedInsp`
|
|
object.
|
|
|
|
This is the "target" or "remote" side of the
|
|
:func:`.relationship`.
|
|
|
|
"""
|
|
return self.property.entity
|
|
|
|
@util.memoized_property
|
|
def mapper(self):
|
|
"""The target :class:`.Mapper` referred to by this
|
|
:class:`.RelationshipProperty.Comparator`.
|
|
|
|
This is the "target" or "remote" side of the
|
|
:func:`.relationship`.
|
|
|
|
"""
|
|
return self.property.mapper
|
|
|
|
@util.memoized_property
|
|
def _parententity(self):
|
|
return self.property.parent
|
|
|
|
def _source_selectable(self):
|
|
if self._adapt_to_entity:
|
|
return self._adapt_to_entity.selectable
|
|
else:
|
|
return self.property.parent._with_polymorphic_selectable
|
|
|
|
def __clause_element__(self):
|
|
adapt_from = self._source_selectable()
|
|
if self._of_type:
|
|
of_type_mapper = inspect(self._of_type).mapper
|
|
else:
|
|
of_type_mapper = None
|
|
|
|
(
|
|
pj,
|
|
sj,
|
|
source,
|
|
dest,
|
|
secondary,
|
|
target_adapter,
|
|
) = self.property._create_joins(
|
|
source_selectable=adapt_from,
|
|
source_polymorphic=True,
|
|
of_type_mapper=of_type_mapper,
|
|
)
|
|
if sj is not None:
|
|
return pj & sj
|
|
else:
|
|
return pj
|
|
|
|
def of_type(self, cls):
|
|
r"""Redefine this object in terms of a polymorphic subclass.
|
|
|
|
See :meth:`.PropComparator.of_type` for an example.
|
|
|
|
"""
|
|
return RelationshipProperty.Comparator(
|
|
self.property,
|
|
self._parententity,
|
|
adapt_to_entity=self._adapt_to_entity,
|
|
of_type=cls,
|
|
)
|
|
|
|
def in_(self, other):
|
|
"""Produce an IN clause - this is not implemented
|
|
for :func:`~.orm.relationship`-based attributes at this time.
|
|
|
|
"""
|
|
raise NotImplementedError(
|
|
"in_() not yet supported for "
|
|
"relationships. For a simple "
|
|
"many-to-one, use in_() against "
|
|
"the set of foreign key values."
|
|
)
|
|
|
|
__hash__ = None
|
|
|
|
def __eq__(self, other):
|
|
"""Implement the ``==`` operator.
|
|
|
|
In a many-to-one context, such as::
|
|
|
|
MyClass.some_prop == <some object>
|
|
|
|
this will typically produce a
|
|
clause such as::
|
|
|
|
mytable.related_id == <some id>
|
|
|
|
Where ``<some id>`` is the primary key of the given
|
|
object.
|
|
|
|
The ``==`` operator provides partial functionality for non-
|
|
many-to-one comparisons:
|
|
|
|
* Comparisons against collections are not supported.
|
|
Use :meth:`~.RelationshipProperty.Comparator.contains`.
|
|
* Compared to a scalar one-to-many, will produce a
|
|
clause that compares the target columns in the parent to
|
|
the given target.
|
|
* Compared to a scalar many-to-many, an alias
|
|
of the association table will be rendered as
|
|
well, forming a natural join that is part of the
|
|
main body of the query. This will not work for
|
|
queries that go beyond simple AND conjunctions of
|
|
comparisons, such as those which use OR. Use
|
|
explicit joins, outerjoins, or
|
|
:meth:`~.RelationshipProperty.Comparator.has` for
|
|
more comprehensive non-many-to-one scalar
|
|
membership tests.
|
|
* Comparisons against ``None`` given in a one-to-many
|
|
or many-to-many context produce a NOT EXISTS clause.
|
|
|
|
"""
|
|
if isinstance(other, (util.NoneType, expression.Null)):
|
|
if self.property.direction in [ONETOMANY, MANYTOMANY]:
|
|
return ~self._criterion_exists()
|
|
else:
|
|
return _orm_annotate(
|
|
self.property._optimized_compare(
|
|
None, adapt_source=self.adapter
|
|
)
|
|
)
|
|
elif self.property.uselist:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't compare a collection to an object or collection; "
|
|
"use contains() to test for membership."
|
|
)
|
|
else:
|
|
return _orm_annotate(
|
|
self.property._optimized_compare(
|
|
other, adapt_source=self.adapter
|
|
)
|
|
)
|
|
|
|
def _criterion_exists(self, criterion=None, **kwargs):
|
|
if getattr(self, "_of_type", None):
|
|
info = inspect(self._of_type)
|
|
target_mapper, to_selectable, is_aliased_class = (
|
|
info.mapper,
|
|
info.selectable,
|
|
info.is_aliased_class,
|
|
)
|
|
if self.property._is_self_referential and not is_aliased_class:
|
|
to_selectable = to_selectable.alias()
|
|
|
|
single_crit = target_mapper._single_table_criterion
|
|
if single_crit is not None:
|
|
if criterion is not None:
|
|
criterion = single_crit & criterion
|
|
else:
|
|
criterion = single_crit
|
|
else:
|
|
is_aliased_class = False
|
|
to_selectable = None
|
|
|
|
if self.adapter:
|
|
source_selectable = self._source_selectable()
|
|
else:
|
|
source_selectable = None
|
|
|
|
(
|
|
pj,
|
|
sj,
|
|
source,
|
|
dest,
|
|
secondary,
|
|
target_adapter,
|
|
) = self.property._create_joins(
|
|
dest_polymorphic=True,
|
|
dest_selectable=to_selectable,
|
|
source_selectable=source_selectable,
|
|
)
|
|
|
|
for k in kwargs:
|
|
crit = getattr(self.property.mapper.class_, k) == kwargs[k]
|
|
if criterion is None:
|
|
criterion = crit
|
|
else:
|
|
criterion = criterion & crit
|
|
|
|
# annotate the *local* side of the join condition, in the case
|
|
# of pj + sj this is the full primaryjoin, in the case of just
|
|
# pj its the local side of the primaryjoin.
|
|
if sj is not None:
|
|
j = _orm_annotate(pj) & sj
|
|
else:
|
|
j = _orm_annotate(pj, exclude=self.property.remote_side)
|
|
|
|
if (
|
|
criterion is not None
|
|
and target_adapter
|
|
and not is_aliased_class
|
|
):
|
|
# limit this adapter to annotated only?
|
|
criterion = target_adapter.traverse(criterion)
|
|
|
|
# only have the "joined left side" of what we
|
|
# return be subject to Query adaption. The right
|
|
# side of it is used for an exists() subquery and
|
|
# should not correlate or otherwise reach out
|
|
# to anything in the enclosing query.
|
|
if criterion is not None:
|
|
criterion = criterion._annotate(
|
|
{"no_replacement_traverse": True}
|
|
)
|
|
|
|
crit = j & sql.True_._ifnone(criterion)
|
|
|
|
if secondary is not None:
|
|
ex = sql.exists(
|
|
[1], crit, from_obj=[dest, secondary]
|
|
).correlate_except(dest, secondary)
|
|
else:
|
|
ex = sql.exists([1], crit, from_obj=dest).correlate_except(
|
|
dest
|
|
)
|
|
return ex
|
|
|
|
def any(self, criterion=None, **kwargs):
|
|
"""Produce an expression that tests a collection against
|
|
particular criterion, using EXISTS.
|
|
|
|
An expression like::
|
|
|
|
session.query(MyClass).filter(
|
|
MyClass.somereference.any(SomeRelated.x==2)
|
|
)
|
|
|
|
|
|
Will produce a query like::
|
|
|
|
SELECT * FROM my_table WHERE
|
|
EXISTS (SELECT 1 FROM related WHERE related.my_id=my_table.id
|
|
AND related.x=2)
|
|
|
|
Because :meth:`~.RelationshipProperty.Comparator.any` uses
|
|
a correlated subquery, its performance is not nearly as
|
|
good when compared against large target tables as that of
|
|
using a join.
|
|
|
|
:meth:`~.RelationshipProperty.Comparator.any` is particularly
|
|
useful for testing for empty collections::
|
|
|
|
session.query(MyClass).filter(
|
|
~MyClass.somereference.any()
|
|
)
|
|
|
|
will produce::
|
|
|
|
SELECT * FROM my_table WHERE
|
|
NOT EXISTS (SELECT 1 FROM related WHERE
|
|
related.my_id=my_table.id)
|
|
|
|
:meth:`~.RelationshipProperty.Comparator.any` is only
|
|
valid for collections, i.e. a :func:`.relationship`
|
|
that has ``uselist=True``. For scalar references,
|
|
use :meth:`~.RelationshipProperty.Comparator.has`.
|
|
|
|
"""
|
|
if not self.property.uselist:
|
|
raise sa_exc.InvalidRequestError(
|
|
"'any()' not implemented for scalar "
|
|
"attributes. Use has()."
|
|
)
|
|
|
|
return self._criterion_exists(criterion, **kwargs)
|
|
|
|
def has(self, criterion=None, **kwargs):
|
|
"""Produce an expression that tests a scalar reference against
|
|
particular criterion, using EXISTS.
|
|
|
|
An expression like::
|
|
|
|
session.query(MyClass).filter(
|
|
MyClass.somereference.has(SomeRelated.x==2)
|
|
)
|
|
|
|
|
|
Will produce a query like::
|
|
|
|
SELECT * FROM my_table WHERE
|
|
EXISTS (SELECT 1 FROM related WHERE
|
|
related.id==my_table.related_id AND related.x=2)
|
|
|
|
Because :meth:`~.RelationshipProperty.Comparator.has` uses
|
|
a correlated subquery, its performance is not nearly as
|
|
good when compared against large target tables as that of
|
|
using a join.
|
|
|
|
:meth:`~.RelationshipProperty.Comparator.has` is only
|
|
valid for scalar references, i.e. a :func:`.relationship`
|
|
that has ``uselist=False``. For collection references,
|
|
use :meth:`~.RelationshipProperty.Comparator.any`.
|
|
|
|
"""
|
|
if self.property.uselist:
|
|
raise sa_exc.InvalidRequestError(
|
|
"'has()' not implemented for collections. " "Use any()."
|
|
)
|
|
return self._criterion_exists(criterion, **kwargs)
|
|
|
|
def contains(self, other, **kwargs):
|
|
"""Return a simple expression that tests a collection for
|
|
containment of a particular item.
|
|
|
|
:meth:`~.RelationshipProperty.Comparator.contains` is
|
|
only valid for a collection, i.e. a
|
|
:func:`~.orm.relationship` that implements
|
|
one-to-many or many-to-many with ``uselist=True``.
|
|
|
|
When used in a simple one-to-many context, an
|
|
expression like::
|
|
|
|
MyClass.contains(other)
|
|
|
|
Produces a clause like::
|
|
|
|
mytable.id == <some id>
|
|
|
|
Where ``<some id>`` is the value of the foreign key
|
|
attribute on ``other`` which refers to the primary
|
|
key of its parent object. From this it follows that
|
|
:meth:`~.RelationshipProperty.Comparator.contains` is
|
|
very useful when used with simple one-to-many
|
|
operations.
|
|
|
|
For many-to-many operations, the behavior of
|
|
:meth:`~.RelationshipProperty.Comparator.contains`
|
|
has more caveats. The association table will be
|
|
rendered in the statement, producing an "implicit"
|
|
join, that is, includes multiple tables in the FROM
|
|
clause which are equated in the WHERE clause::
|
|
|
|
query(MyClass).filter(MyClass.contains(other))
|
|
|
|
Produces a query like::
|
|
|
|
SELECT * FROM my_table, my_association_table AS
|
|
my_association_table_1 WHERE
|
|
my_table.id = my_association_table_1.parent_id
|
|
AND my_association_table_1.child_id = <some id>
|
|
|
|
Where ``<some id>`` would be the primary key of
|
|
``other``. From the above, it is clear that
|
|
:meth:`~.RelationshipProperty.Comparator.contains`
|
|
will **not** work with many-to-many collections when
|
|
used in queries that move beyond simple AND
|
|
conjunctions, such as multiple
|
|
:meth:`~.RelationshipProperty.Comparator.contains`
|
|
expressions joined by OR. In such cases subqueries or
|
|
explicit "outer joins" will need to be used instead.
|
|
See :meth:`~.RelationshipProperty.Comparator.any` for
|
|
a less-performant alternative using EXISTS, or refer
|
|
to :meth:`.Query.outerjoin` as well as :ref:`ormtutorial_joins`
|
|
for more details on constructing outer joins.
|
|
|
|
"""
|
|
if not self.property.uselist:
|
|
raise sa_exc.InvalidRequestError(
|
|
"'contains' not implemented for scalar "
|
|
"attributes. Use =="
|
|
)
|
|
clause = self.property._optimized_compare(
|
|
other, adapt_source=self.adapter
|
|
)
|
|
|
|
if self.property.secondaryjoin is not None:
|
|
clause.negation_clause = self.__negated_contains_or_equals(
|
|
other
|
|
)
|
|
|
|
return clause
|
|
|
|
def __negated_contains_or_equals(self, other):
|
|
if self.property.direction == MANYTOONE:
|
|
state = attributes.instance_state(other)
|
|
|
|
def state_bindparam(x, state, col):
|
|
dict_ = state.dict
|
|
return sql.bindparam(
|
|
x,
|
|
unique=True,
|
|
callable_=self.property._get_attr_w_warn_on_none(
|
|
self.property.mapper, state, dict_, col
|
|
),
|
|
)
|
|
|
|
def adapt(col):
|
|
if self.adapter:
|
|
return self.adapter(col)
|
|
else:
|
|
return col
|
|
|
|
if self.property._use_get:
|
|
return sql.and_(
|
|
*[
|
|
sql.or_(
|
|
adapt(x)
|
|
!= state_bindparam(adapt(x), state, y),
|
|
adapt(x) == None,
|
|
)
|
|
for (x, y) in self.property.local_remote_pairs
|
|
]
|
|
)
|
|
|
|
criterion = sql.and_(
|
|
*[
|
|
x == y
|
|
for (x, y) in zip(
|
|
self.property.mapper.primary_key,
|
|
self.property.mapper.primary_key_from_instance(other),
|
|
)
|
|
]
|
|
)
|
|
|
|
return ~self._criterion_exists(criterion)
|
|
|
|
def __ne__(self, other):
|
|
"""Implement the ``!=`` operator.
|
|
|
|
In a many-to-one context, such as::
|
|
|
|
MyClass.some_prop != <some object>
|
|
|
|
This will typically produce a clause such as::
|
|
|
|
mytable.related_id != <some id>
|
|
|
|
Where ``<some id>`` is the primary key of the
|
|
given object.
|
|
|
|
The ``!=`` operator provides partial functionality for non-
|
|
many-to-one comparisons:
|
|
|
|
* Comparisons against collections are not supported.
|
|
Use
|
|
:meth:`~.RelationshipProperty.Comparator.contains`
|
|
in conjunction with :func:`~.expression.not_`.
|
|
* Compared to a scalar one-to-many, will produce a
|
|
clause that compares the target columns in the parent to
|
|
the given target.
|
|
* Compared to a scalar many-to-many, an alias
|
|
of the association table will be rendered as
|
|
well, forming a natural join that is part of the
|
|
main body of the query. This will not work for
|
|
queries that go beyond simple AND conjunctions of
|
|
comparisons, such as those which use OR. Use
|
|
explicit joins, outerjoins, or
|
|
:meth:`~.RelationshipProperty.Comparator.has` in
|
|
conjunction with :func:`~.expression.not_` for
|
|
more comprehensive non-many-to-one scalar
|
|
membership tests.
|
|
* Comparisons against ``None`` given in a one-to-many
|
|
or many-to-many context produce an EXISTS clause.
|
|
|
|
"""
|
|
if isinstance(other, (util.NoneType, expression.Null)):
|
|
if self.property.direction == MANYTOONE:
|
|
return _orm_annotate(
|
|
~self.property._optimized_compare(
|
|
None, adapt_source=self.adapter
|
|
)
|
|
)
|
|
|
|
else:
|
|
return self._criterion_exists()
|
|
elif self.property.uselist:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't compare a collection"
|
|
" to an object or collection; use "
|
|
"contains() to test for membership."
|
|
)
|
|
else:
|
|
return _orm_annotate(self.__negated_contains_or_equals(other))
|
|
|
|
@util.memoized_property
|
|
def property(self):
|
|
if mapperlib.Mapper._new_mappers:
|
|
mapperlib.Mapper._configure_all()
|
|
return self.prop
|
|
|
|
def _with_parent(self, instance, alias_secondary=True, from_entity=None):
|
|
assert instance is not None
|
|
adapt_source = None
|
|
if from_entity is not None:
|
|
insp = inspect(from_entity)
|
|
if insp.is_aliased_class:
|
|
adapt_source = insp._adapter.adapt_clause
|
|
return self._optimized_compare(
|
|
instance,
|
|
value_is_parent=True,
|
|
adapt_source=adapt_source,
|
|
alias_secondary=alias_secondary,
|
|
)
|
|
|
|
def _optimized_compare(
|
|
self,
|
|
state,
|
|
value_is_parent=False,
|
|
adapt_source=None,
|
|
alias_secondary=True,
|
|
):
|
|
if state is not None:
|
|
state = attributes.instance_state(state)
|
|
|
|
reverse_direction = not value_is_parent
|
|
|
|
if state is None:
|
|
return self._lazy_none_clause(
|
|
reverse_direction, adapt_source=adapt_source
|
|
)
|
|
|
|
if not reverse_direction:
|
|
criterion, bind_to_col = (
|
|
self._lazy_strategy._lazywhere,
|
|
self._lazy_strategy._bind_to_col,
|
|
)
|
|
else:
|
|
criterion, bind_to_col = (
|
|
self._lazy_strategy._rev_lazywhere,
|
|
self._lazy_strategy._rev_bind_to_col,
|
|
)
|
|
|
|
if reverse_direction:
|
|
mapper = self.mapper
|
|
else:
|
|
mapper = self.parent
|
|
|
|
dict_ = attributes.instance_dict(state.obj())
|
|
|
|
def visit_bindparam(bindparam):
|
|
if bindparam._identifying_key in bind_to_col:
|
|
bindparam.callable = self._get_attr_w_warn_on_none(
|
|
mapper,
|
|
state,
|
|
dict_,
|
|
bind_to_col[bindparam._identifying_key],
|
|
)
|
|
|
|
if self.secondary is not None and alias_secondary:
|
|
criterion = ClauseAdapter(self.secondary.alias()).traverse(
|
|
criterion
|
|
)
|
|
|
|
criterion = visitors.cloned_traverse(
|
|
criterion, {}, {"bindparam": visit_bindparam}
|
|
)
|
|
|
|
if adapt_source:
|
|
criterion = adapt_source(criterion)
|
|
return criterion
|
|
|
|
def _get_attr_w_warn_on_none(self, mapper, state, dict_, column):
|
|
"""Create the callable that is used in a many-to-one expression.
|
|
|
|
E.g.::
|
|
|
|
u1 = s.query(User).get(5)
|
|
|
|
expr = Address.user == u1
|
|
|
|
Above, the SQL should be "address.user_id = 5". The callable
|
|
returned by this method produces the value "5" based on the identity
|
|
of ``u1``.
|
|
|
|
"""
|
|
|
|
# in this callable, we're trying to thread the needle through
|
|
# a wide variety of scenarios, including:
|
|
#
|
|
# * the object hasn't been flushed yet and there's no value for
|
|
# the attribute as of yet
|
|
#
|
|
# * the object hasn't been flushed yet but it has a user-defined
|
|
# value
|
|
#
|
|
# * the object has a value but it's expired and not locally present
|
|
#
|
|
# * the object has a value but it's expired and not locally present,
|
|
# and the object is also detached
|
|
#
|
|
# * The object hadn't been flushed yet, there was no value, but
|
|
# later, the object has been expired and detached, and *now*
|
|
# they're trying to evaluate it
|
|
#
|
|
# * the object had a value, but it was changed to a new value, and
|
|
# then expired
|
|
#
|
|
# * the object had a value, but it was changed to a new value, and
|
|
# then expired, then the object was detached
|
|
#
|
|
# * the object has a user-set value, but it's None and we don't do
|
|
# the comparison correctly for that so warn
|
|
#
|
|
|
|
prop = mapper.get_property_by_column(column)
|
|
|
|
# by invoking this method, InstanceState will track the last known
|
|
# value for this key each time the attribute is to be expired.
|
|
# this feature was added explicitly for use in this method.
|
|
state._track_last_known_value(prop.key)
|
|
|
|
def _go():
|
|
last_known = to_return = state._last_known_values[prop.key]
|
|
existing_is_available = last_known is not attributes.NO_VALUE
|
|
|
|
# we support that the value may have changed. so here we
|
|
# try to get the most recent value including re-fetching.
|
|
# only if we can't get a value now due to detachment do we return
|
|
# the last known value
|
|
current_value = mapper._get_state_attr_by_column(
|
|
state,
|
|
dict_,
|
|
column,
|
|
passive=attributes.PASSIVE_OFF
|
|
if state.persistent
|
|
else attributes.PASSIVE_NO_FETCH ^ attributes.INIT_OK,
|
|
)
|
|
|
|
if current_value is attributes.NEVER_SET:
|
|
if not existing_is_available:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't resolve value for column %s on object "
|
|
"%s; no value has been set for this column"
|
|
% (column, state_str(state))
|
|
)
|
|
elif current_value is attributes.PASSIVE_NO_RESULT:
|
|
if not existing_is_available:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't resolve value for column %s on object "
|
|
"%s; the object is detached and the value was "
|
|
"expired" % (column, state_str(state))
|
|
)
|
|
else:
|
|
to_return = current_value
|
|
if to_return is None:
|
|
util.warn(
|
|
"Got None for value of column %s; this is unsupported "
|
|
"for a relationship comparison and will not "
|
|
"currently produce an IS comparison "
|
|
"(but may in a future release)" % column
|
|
)
|
|
return to_return
|
|
|
|
return _go
|
|
|
|
def _lazy_none_clause(self, reverse_direction=False, adapt_source=None):
|
|
if not reverse_direction:
|
|
criterion, bind_to_col = (
|
|
self._lazy_strategy._lazywhere,
|
|
self._lazy_strategy._bind_to_col,
|
|
)
|
|
else:
|
|
criterion, bind_to_col = (
|
|
self._lazy_strategy._rev_lazywhere,
|
|
self._lazy_strategy._rev_bind_to_col,
|
|
)
|
|
|
|
criterion = adapt_criterion_to_null(criterion, bind_to_col)
|
|
|
|
if adapt_source:
|
|
criterion = adapt_source(criterion)
|
|
return criterion
|
|
|
|
def __str__(self):
|
|
return str(self.parent.class_.__name__) + "." + self.key
|
|
|
|
def merge(
|
|
self,
|
|
session,
|
|
source_state,
|
|
source_dict,
|
|
dest_state,
|
|
dest_dict,
|
|
load,
|
|
_recursive,
|
|
_resolve_conflict_map,
|
|
):
|
|
|
|
if load:
|
|
for r in self._reverse_property:
|
|
if (source_state, r) in _recursive:
|
|
return
|
|
|
|
if "merge" not in self._cascade:
|
|
return
|
|
|
|
if self.key not in source_dict:
|
|
return
|
|
|
|
if self.uselist:
|
|
instances = source_state.get_impl(self.key).get(
|
|
source_state, source_dict
|
|
)
|
|
if hasattr(instances, "_sa_adapter"):
|
|
# convert collections to adapters to get a true iterator
|
|
instances = instances._sa_adapter
|
|
|
|
if load:
|
|
# for a full merge, pre-load the destination collection,
|
|
# so that individual _merge of each item pulls from identity
|
|
# map for those already present.
|
|
# also assumes CollectionAttributeImpl behavior of loading
|
|
# "old" list in any case
|
|
dest_state.get_impl(self.key).get(dest_state, dest_dict)
|
|
|
|
dest_list = []
|
|
for current in instances:
|
|
current_state = attributes.instance_state(current)
|
|
current_dict = attributes.instance_dict(current)
|
|
_recursive[(current_state, self)] = True
|
|
obj = session._merge(
|
|
current_state,
|
|
current_dict,
|
|
load=load,
|
|
_recursive=_recursive,
|
|
_resolve_conflict_map=_resolve_conflict_map,
|
|
)
|
|
if obj is not None:
|
|
dest_list.append(obj)
|
|
|
|
if not load:
|
|
coll = attributes.init_state_collection(
|
|
dest_state, dest_dict, self.key
|
|
)
|
|
for c in dest_list:
|
|
coll.append_without_event(c)
|
|
else:
|
|
dest_state.get_impl(self.key).set(
|
|
dest_state, dest_dict, dest_list, _adapt=False
|
|
)
|
|
else:
|
|
current = source_dict[self.key]
|
|
if current is not None:
|
|
current_state = attributes.instance_state(current)
|
|
current_dict = attributes.instance_dict(current)
|
|
_recursive[(current_state, self)] = True
|
|
obj = session._merge(
|
|
current_state,
|
|
current_dict,
|
|
load=load,
|
|
_recursive=_recursive,
|
|
_resolve_conflict_map=_resolve_conflict_map,
|
|
)
|
|
else:
|
|
obj = None
|
|
|
|
if not load:
|
|
dest_dict[self.key] = obj
|
|
else:
|
|
dest_state.get_impl(self.key).set(
|
|
dest_state, dest_dict, obj, None
|
|
)
|
|
|
|
def _value_as_iterable(
|
|
self, state, dict_, key, passive=attributes.PASSIVE_OFF
|
|
):
|
|
"""Return a list of tuples (state, obj) for the given
|
|
key.
|
|
|
|
returns an empty list if the value is None/empty/PASSIVE_NO_RESULT
|
|
"""
|
|
|
|
impl = state.manager[key].impl
|
|
x = impl.get(state, dict_, passive=passive)
|
|
if x is attributes.PASSIVE_NO_RESULT or x is None:
|
|
return []
|
|
elif hasattr(impl, "get_collection"):
|
|
return [
|
|
(attributes.instance_state(o), o)
|
|
for o in impl.get_collection(state, dict_, x, passive=passive)
|
|
]
|
|
else:
|
|
return [(attributes.instance_state(x), x)]
|
|
|
|
def cascade_iterator(
|
|
self, type_, state, dict_, visited_states, halt_on=None
|
|
):
|
|
# assert type_ in self._cascade
|
|
|
|
# only actively lazy load on the 'delete' cascade
|
|
if type_ != "delete" or self.passive_deletes:
|
|
passive = attributes.PASSIVE_NO_INITIALIZE
|
|
else:
|
|
passive = attributes.PASSIVE_OFF
|
|
|
|
if type_ == "save-update":
|
|
tuples = state.manager[self.key].impl.get_all_pending(state, dict_)
|
|
|
|
else:
|
|
tuples = self._value_as_iterable(
|
|
state, dict_, self.key, passive=passive
|
|
)
|
|
|
|
skip_pending = (
|
|
type_ == "refresh-expire" and "delete-orphan" not in self._cascade
|
|
)
|
|
|
|
for instance_state, c in tuples:
|
|
if instance_state in visited_states:
|
|
continue
|
|
|
|
if c is None:
|
|
# would like to emit a warning here, but
|
|
# would not be consistent with collection.append(None)
|
|
# current behavior of silently skipping.
|
|
# see [ticket:2229]
|
|
continue
|
|
|
|
instance_dict = attributes.instance_dict(c)
|
|
|
|
if halt_on and halt_on(instance_state):
|
|
continue
|
|
|
|
if skip_pending and not instance_state.key:
|
|
continue
|
|
|
|
instance_mapper = instance_state.manager.mapper
|
|
|
|
if not instance_mapper.isa(self.mapper.class_manager.mapper):
|
|
raise AssertionError(
|
|
"Attribute '%s' on class '%s' "
|
|
"doesn't handle objects "
|
|
"of type '%s'"
|
|
% (self.key, self.parent.class_, c.__class__)
|
|
)
|
|
|
|
visited_states.add(instance_state)
|
|
|
|
yield c, instance_mapper, instance_state, instance_dict
|
|
|
|
def _add_reverse_property(self, key):
|
|
other = self.mapper.get_property(key, _configure_mappers=False)
|
|
self._reverse_property.add(other)
|
|
other._reverse_property.add(self)
|
|
|
|
if not other.mapper.common_parent(self.parent):
|
|
raise sa_exc.ArgumentError(
|
|
"reverse_property %r on "
|
|
"relationship %s references relationship %s, which "
|
|
"does not reference mapper %s"
|
|
% (key, self, other, self.parent)
|
|
)
|
|
|
|
if (
|
|
self.direction in (ONETOMANY, MANYTOONE)
|
|
and self.direction == other.direction
|
|
):
|
|
raise sa_exc.ArgumentError(
|
|
"%s and back-reference %s are "
|
|
"both of the same direction %r. Did you mean to "
|
|
"set remote_side on the many-to-one side ?"
|
|
% (other, self, self.direction)
|
|
)
|
|
|
|
@util.memoized_property
|
|
def entity(self): # type: () -> Union[AliasedInsp, Mapper]
|
|
"""Return the target mapped entity, which is an inspect() of the
|
|
class or aliased class tha is referred towards.
|
|
|
|
"""
|
|
if util.callable(self.argument) and not isinstance(
|
|
self.argument, (type, mapperlib.Mapper)
|
|
):
|
|
argument = self.argument()
|
|
else:
|
|
argument = self.argument
|
|
|
|
if isinstance(argument, type):
|
|
return mapperlib.class_mapper(argument, configure=False)
|
|
|
|
try:
|
|
entity = inspect(argument)
|
|
except sa_exc.NoInspectionAvailable:
|
|
pass
|
|
else:
|
|
if hasattr(entity, "mapper"):
|
|
return entity
|
|
|
|
raise sa_exc.ArgumentError(
|
|
"relationship '%s' expects "
|
|
"a class or a mapper argument (received: %s)"
|
|
% (self.key, type(argument))
|
|
)
|
|
|
|
@util.memoized_property
|
|
def mapper(self):
|
|
"""Return the targeted :class:`.Mapper` for this
|
|
:class:`.RelationshipProperty`.
|
|
|
|
This is a lazy-initializing static attribute.
|
|
|
|
"""
|
|
return self.entity.mapper
|
|
|
|
def do_init(self):
|
|
self._check_conflicts()
|
|
self._process_dependent_arguments()
|
|
self._setup_join_conditions()
|
|
self._check_cascade_settings(self._cascade)
|
|
self._post_init()
|
|
self._generate_backref()
|
|
self._join_condition._warn_for_conflicting_sync_targets()
|
|
super(RelationshipProperty, self).do_init()
|
|
self._lazy_strategy = self._get_strategy((("lazy", "select"),))
|
|
|
|
def _process_dependent_arguments(self):
|
|
"""Convert incoming configuration arguments to their
|
|
proper form.
|
|
|
|
Callables are resolved, ORM annotations removed.
|
|
|
|
"""
|
|
# accept callables for other attributes which may require
|
|
# deferred initialization. This technique is used
|
|
# by declarative "string configs" and some recipes.
|
|
for attr in (
|
|
"order_by",
|
|
"primaryjoin",
|
|
"secondaryjoin",
|
|
"secondary",
|
|
"_user_defined_foreign_keys",
|
|
"remote_side",
|
|
):
|
|
attr_value = getattr(self, attr)
|
|
if util.callable(attr_value):
|
|
setattr(self, attr, attr_value())
|
|
|
|
# remove "annotations" which are present if mapped class
|
|
# descriptors are used to create the join expression.
|
|
for attr in "primaryjoin", "secondaryjoin":
|
|
val = getattr(self, attr)
|
|
if val is not None:
|
|
setattr(
|
|
self,
|
|
attr,
|
|
_orm_deannotate(
|
|
expression._only_column_elements(val, attr)
|
|
),
|
|
)
|
|
|
|
# ensure expressions in self.order_by, foreign_keys,
|
|
# remote_side are all columns, not strings.
|
|
if self.order_by is not False and self.order_by is not None:
|
|
self.order_by = [
|
|
expression._only_column_elements(x, "order_by")
|
|
for x in util.to_list(self.order_by)
|
|
]
|
|
|
|
self._user_defined_foreign_keys = util.column_set(
|
|
expression._only_column_elements(x, "foreign_keys")
|
|
for x in util.to_column_set(self._user_defined_foreign_keys)
|
|
)
|
|
|
|
self.remote_side = util.column_set(
|
|
expression._only_column_elements(x, "remote_side")
|
|
for x in util.to_column_set(self.remote_side)
|
|
)
|
|
|
|
self.target = self.entity.persist_selectable
|
|
|
|
def _setup_join_conditions(self):
|
|
self._join_condition = jc = JoinCondition(
|
|
parent_persist_selectable=self.parent.persist_selectable,
|
|
child_persist_selectable=self.entity.persist_selectable,
|
|
parent_local_selectable=self.parent.local_table,
|
|
child_local_selectable=self.entity.local_table,
|
|
primaryjoin=self.primaryjoin,
|
|
secondary=self.secondary,
|
|
secondaryjoin=self.secondaryjoin,
|
|
parent_equivalents=self.parent._equivalent_columns,
|
|
child_equivalents=self.mapper._equivalent_columns,
|
|
consider_as_foreign_keys=self._user_defined_foreign_keys,
|
|
local_remote_pairs=self.local_remote_pairs,
|
|
remote_side=self.remote_side,
|
|
self_referential=self._is_self_referential,
|
|
prop=self,
|
|
support_sync=not self.viewonly,
|
|
can_be_synced_fn=self._columns_are_mapped,
|
|
)
|
|
self.primaryjoin = jc.primaryjoin
|
|
self.secondaryjoin = jc.secondaryjoin
|
|
self.direction = jc.direction
|
|
self.local_remote_pairs = jc.local_remote_pairs
|
|
self.remote_side = jc.remote_columns
|
|
self.local_columns = jc.local_columns
|
|
self.synchronize_pairs = jc.synchronize_pairs
|
|
self._calculated_foreign_keys = jc.foreign_key_columns
|
|
self.secondary_synchronize_pairs = jc.secondary_synchronize_pairs
|
|
|
|
def _check_conflicts(self):
|
|
"""Test that this relationship is legal, warn about
|
|
inheritance conflicts."""
|
|
|
|
if self.parent.non_primary and not mapperlib.class_mapper(
|
|
self.parent.class_, configure=False
|
|
).has_property(self.key):
|
|
raise sa_exc.ArgumentError(
|
|
"Attempting to assign a new "
|
|
"relationship '%s' to a non-primary mapper on "
|
|
"class '%s'. New relationships can only be added "
|
|
"to the primary mapper, i.e. the very first mapper "
|
|
"created for class '%s' "
|
|
% (
|
|
self.key,
|
|
self.parent.class_.__name__,
|
|
self.parent.class_.__name__,
|
|
)
|
|
)
|
|
|
|
def _get_cascade(self):
|
|
"""Return the current cascade setting for this
|
|
:class:`.RelationshipProperty`.
|
|
"""
|
|
return self._cascade
|
|
|
|
def _set_cascade(self, cascade):
|
|
cascade = CascadeOptions(cascade)
|
|
if "mapper" in self.__dict__:
|
|
self._check_cascade_settings(cascade)
|
|
self._cascade = cascade
|
|
|
|
if self._dependency_processor:
|
|
self._dependency_processor.cascade = cascade
|
|
|
|
cascade = property(_get_cascade, _set_cascade)
|
|
|
|
def _check_cascade_settings(self, cascade):
|
|
if (
|
|
cascade.delete_orphan
|
|
and not self.single_parent
|
|
and (self.direction is MANYTOMANY or self.direction is MANYTOONE)
|
|
):
|
|
raise sa_exc.ArgumentError(
|
|
"On %s, delete-orphan cascade is not supported "
|
|
"on a many-to-many or many-to-one relationship "
|
|
"when single_parent is not set. Set "
|
|
"single_parent=True on the relationship()." % self
|
|
)
|
|
if self.direction is MANYTOONE and self.passive_deletes:
|
|
util.warn(
|
|
"On %s, 'passive_deletes' is normally configured "
|
|
"on one-to-many, one-to-one, many-to-many "
|
|
"relationships only." % self
|
|
)
|
|
|
|
if self.passive_deletes == "all" and (
|
|
"delete" in cascade or "delete-orphan" in cascade
|
|
):
|
|
raise sa_exc.ArgumentError(
|
|
"On %s, can't set passive_deletes='all' in conjunction "
|
|
"with 'delete' or 'delete-orphan' cascade" % self
|
|
)
|
|
|
|
if cascade.delete_orphan:
|
|
self.mapper.primary_mapper()._delete_orphans.append(
|
|
(self.key, self.parent.class_)
|
|
)
|
|
|
|
def _persists_for(self, mapper):
|
|
"""Return True if this property will persist values on behalf
|
|
of the given mapper.
|
|
|
|
"""
|
|
|
|
return (
|
|
self.key in mapper.relationships
|
|
and mapper.relationships[self.key] is self
|
|
)
|
|
|
|
def _columns_are_mapped(self, *cols):
|
|
"""Return True if all columns in the given collection are
|
|
mapped by the tables referenced by this :class:`.Relationship`.
|
|
|
|
"""
|
|
for c in cols:
|
|
if (
|
|
self.secondary is not None
|
|
and self.secondary.c.contains_column(c)
|
|
):
|
|
continue
|
|
if not self.parent.persist_selectable.c.contains_column(
|
|
c
|
|
) and not self.target.c.contains_column(c):
|
|
return False
|
|
return True
|
|
|
|
def _generate_backref(self):
|
|
"""Interpret the 'backref' instruction to create a
|
|
:func:`.relationship` complementary to this one."""
|
|
|
|
if self.parent.non_primary:
|
|
return
|
|
if self.backref is not None and not self.back_populates:
|
|
if isinstance(self.backref, util.string_types):
|
|
backref_key, kwargs = self.backref, {}
|
|
else:
|
|
backref_key, kwargs = self.backref
|
|
mapper = self.mapper.primary_mapper()
|
|
|
|
if not mapper.concrete:
|
|
check = set(mapper.iterate_to_root()).union(
|
|
mapper.self_and_descendants
|
|
)
|
|
for m in check:
|
|
if m.has_property(backref_key) and not m.concrete:
|
|
raise sa_exc.ArgumentError(
|
|
"Error creating backref "
|
|
"'%s' on relationship '%s': property of that "
|
|
"name exists on mapper '%s'"
|
|
% (backref_key, self, m)
|
|
)
|
|
|
|
# determine primaryjoin/secondaryjoin for the
|
|
# backref. Use the one we had, so that
|
|
# a custom join doesn't have to be specified in
|
|
# both directions.
|
|
if self.secondary is not None:
|
|
# for many to many, just switch primaryjoin/
|
|
# secondaryjoin. use the annotated
|
|
# pj/sj on the _join_condition.
|
|
pj = kwargs.pop(
|
|
"primaryjoin",
|
|
self._join_condition.secondaryjoin_minus_local,
|
|
)
|
|
sj = kwargs.pop(
|
|
"secondaryjoin",
|
|
self._join_condition.primaryjoin_minus_local,
|
|
)
|
|
else:
|
|
pj = kwargs.pop(
|
|
"primaryjoin",
|
|
self._join_condition.primaryjoin_reverse_remote,
|
|
)
|
|
sj = kwargs.pop("secondaryjoin", None)
|
|
if sj:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't assign 'secondaryjoin' on a backref "
|
|
"against a non-secondary relationship."
|
|
)
|
|
|
|
foreign_keys = kwargs.pop(
|
|
"foreign_keys", self._user_defined_foreign_keys
|
|
)
|
|
parent = self.parent.primary_mapper()
|
|
kwargs.setdefault("viewonly", self.viewonly)
|
|
kwargs.setdefault("post_update", self.post_update)
|
|
kwargs.setdefault("passive_updates", self.passive_updates)
|
|
self.back_populates = backref_key
|
|
relationship = RelationshipProperty(
|
|
parent,
|
|
self.secondary,
|
|
pj,
|
|
sj,
|
|
foreign_keys=foreign_keys,
|
|
back_populates=self.key,
|
|
**kwargs
|
|
)
|
|
mapper._configure_property(backref_key, relationship)
|
|
|
|
if self.back_populates:
|
|
self._add_reverse_property(self.back_populates)
|
|
|
|
def _post_init(self):
|
|
if self.uselist is None:
|
|
self.uselist = self.direction is not MANYTOONE
|
|
if not self.viewonly:
|
|
self._dependency_processor = (
|
|
dependency.DependencyProcessor.from_relationship
|
|
)(self)
|
|
|
|
@util.memoized_property
|
|
def _use_get(self):
|
|
"""memoize the 'use_get' attribute of this RelationshipLoader's
|
|
lazyloader."""
|
|
|
|
strategy = self._lazy_strategy
|
|
return strategy.use_get
|
|
|
|
@util.memoized_property
|
|
def _is_self_referential(self):
|
|
return self.mapper.common_parent(self.parent)
|
|
|
|
def _create_joins(
|
|
self,
|
|
source_polymorphic=False,
|
|
source_selectable=None,
|
|
dest_polymorphic=False,
|
|
dest_selectable=None,
|
|
of_type_mapper=None,
|
|
):
|
|
if source_selectable is None:
|
|
if source_polymorphic and self.parent.with_polymorphic:
|
|
source_selectable = self.parent._with_polymorphic_selectable
|
|
|
|
aliased = False
|
|
if dest_selectable is None:
|
|
dest_selectable = self.entity.selectable
|
|
if dest_polymorphic and self.mapper.with_polymorphic:
|
|
aliased = True
|
|
|
|
if self._is_self_referential and source_selectable is None:
|
|
dest_selectable = dest_selectable.alias()
|
|
aliased = True
|
|
else:
|
|
aliased = True
|
|
|
|
dest_mapper = of_type_mapper or self.mapper
|
|
|
|
single_crit = dest_mapper._single_table_criterion
|
|
aliased = aliased or (source_selectable is not None)
|
|
|
|
(
|
|
primaryjoin,
|
|
secondaryjoin,
|
|
secondary,
|
|
target_adapter,
|
|
dest_selectable,
|
|
) = self._join_condition.join_targets(
|
|
source_selectable, dest_selectable, aliased, single_crit
|
|
)
|
|
if source_selectable is None:
|
|
source_selectable = self.parent.local_table
|
|
if dest_selectable is None:
|
|
dest_selectable = self.entity.local_table
|
|
return (
|
|
primaryjoin,
|
|
secondaryjoin,
|
|
source_selectable,
|
|
dest_selectable,
|
|
secondary,
|
|
target_adapter,
|
|
)
|
|
|
|
|
|
def _annotate_columns(element, annotations):
|
|
def clone(elem):
|
|
if isinstance(elem, expression.ColumnClause):
|
|
elem = elem._annotate(annotations.copy())
|
|
elem._copy_internals(clone=clone)
|
|
return elem
|
|
|
|
if element is not None:
|
|
element = clone(element)
|
|
return element
|
|
|
|
|
|
class JoinCondition(object):
|
|
def __init__(
|
|
self,
|
|
parent_persist_selectable,
|
|
child_persist_selectable,
|
|
parent_local_selectable,
|
|
child_local_selectable,
|
|
primaryjoin=None,
|
|
secondary=None,
|
|
secondaryjoin=None,
|
|
parent_equivalents=None,
|
|
child_equivalents=None,
|
|
consider_as_foreign_keys=None,
|
|
local_remote_pairs=None,
|
|
remote_side=None,
|
|
self_referential=False,
|
|
prop=None,
|
|
support_sync=True,
|
|
can_be_synced_fn=lambda *c: True,
|
|
):
|
|
self.parent_persist_selectable = parent_persist_selectable
|
|
self.parent_local_selectable = parent_local_selectable
|
|
self.child_persist_selectable = child_persist_selectable
|
|
self.child_local_selectable = child_local_selectable
|
|
self.parent_equivalents = parent_equivalents
|
|
self.child_equivalents = child_equivalents
|
|
self.primaryjoin = primaryjoin
|
|
self.secondaryjoin = secondaryjoin
|
|
self.secondary = secondary
|
|
self.consider_as_foreign_keys = consider_as_foreign_keys
|
|
self._local_remote_pairs = local_remote_pairs
|
|
self._remote_side = remote_side
|
|
self.prop = prop
|
|
self.self_referential = self_referential
|
|
self.support_sync = support_sync
|
|
self.can_be_synced_fn = can_be_synced_fn
|
|
self._determine_joins()
|
|
self._sanitize_joins()
|
|
self._annotate_fks()
|
|
self._annotate_remote()
|
|
self._annotate_local()
|
|
self._annotate_parentmapper()
|
|
self._setup_pairs()
|
|
self._check_foreign_cols(self.primaryjoin, True)
|
|
if self.secondaryjoin is not None:
|
|
self._check_foreign_cols(self.secondaryjoin, False)
|
|
self._determine_direction()
|
|
self._check_remote_side()
|
|
self._log_joins()
|
|
|
|
def _log_joins(self):
|
|
if self.prop is None:
|
|
return
|
|
log = self.prop.logger
|
|
log.info("%s setup primary join %s", self.prop, self.primaryjoin)
|
|
log.info("%s setup secondary join %s", self.prop, self.secondaryjoin)
|
|
log.info(
|
|
"%s synchronize pairs [%s]",
|
|
self.prop,
|
|
",".join(
|
|
"(%s => %s)" % (l, r) for (l, r) in self.synchronize_pairs
|
|
),
|
|
)
|
|
log.info(
|
|
"%s secondary synchronize pairs [%s]",
|
|
self.prop,
|
|
",".join(
|
|
"(%s => %s)" % (l, r)
|
|
for (l, r) in self.secondary_synchronize_pairs or []
|
|
),
|
|
)
|
|
log.info(
|
|
"%s local/remote pairs [%s]",
|
|
self.prop,
|
|
",".join(
|
|
"(%s / %s)" % (l, r) for (l, r) in self.local_remote_pairs
|
|
),
|
|
)
|
|
log.info(
|
|
"%s remote columns [%s]",
|
|
self.prop,
|
|
",".join("%s" % col for col in self.remote_columns),
|
|
)
|
|
log.info(
|
|
"%s local columns [%s]",
|
|
self.prop,
|
|
",".join("%s" % col for col in self.local_columns),
|
|
)
|
|
log.info("%s relationship direction %s", self.prop, self.direction)
|
|
|
|
def _sanitize_joins(self):
|
|
"""remove the parententity annotation from our join conditions which
|
|
can leak in here based on some declarative patterns and maybe others.
|
|
|
|
We'd want to remove "parentmapper" also, but apparently there's
|
|
an exotic use case in _join_fixture_inh_selfref_w_entity
|
|
that relies upon it being present, see :ticket:`3364`.
|
|
|
|
"""
|
|
|
|
self.primaryjoin = _deep_deannotate(
|
|
self.primaryjoin, values=("parententity",)
|
|
)
|
|
if self.secondaryjoin is not None:
|
|
self.secondaryjoin = _deep_deannotate(
|
|
self.secondaryjoin, values=("parententity",)
|
|
)
|
|
|
|
def _determine_joins(self):
|
|
"""Determine the 'primaryjoin' and 'secondaryjoin' attributes,
|
|
if not passed to the constructor already.
|
|
|
|
This is based on analysis of the foreign key relationships
|
|
between the parent and target mapped selectables.
|
|
|
|
"""
|
|
if self.secondaryjoin is not None and self.secondary is None:
|
|
raise sa_exc.ArgumentError(
|
|
"Property %s specified with secondary "
|
|
"join condition but "
|
|
"no secondary argument" % self.prop
|
|
)
|
|
|
|
# find a join between the given mapper's mapped table and
|
|
# the given table. will try the mapper's local table first
|
|
# for more specificity, then if not found will try the more
|
|
# general mapped table, which in the case of inheritance is
|
|
# a join.
|
|
try:
|
|
consider_as_foreign_keys = self.consider_as_foreign_keys or None
|
|
if self.secondary is not None:
|
|
if self.secondaryjoin is None:
|
|
self.secondaryjoin = join_condition(
|
|
self.child_persist_selectable,
|
|
self.secondary,
|
|
a_subset=self.child_local_selectable,
|
|
consider_as_foreign_keys=consider_as_foreign_keys,
|
|
)
|
|
if self.primaryjoin is None:
|
|
self.primaryjoin = join_condition(
|
|
self.parent_persist_selectable,
|
|
self.secondary,
|
|
a_subset=self.parent_local_selectable,
|
|
consider_as_foreign_keys=consider_as_foreign_keys,
|
|
)
|
|
else:
|
|
if self.primaryjoin is None:
|
|
self.primaryjoin = join_condition(
|
|
self.parent_persist_selectable,
|
|
self.child_persist_selectable,
|
|
a_subset=self.parent_local_selectable,
|
|
consider_as_foreign_keys=consider_as_foreign_keys,
|
|
)
|
|
except sa_exc.NoForeignKeysError:
|
|
if self.secondary is not None:
|
|
raise sa_exc.NoForeignKeysError(
|
|
"Could not determine join "
|
|
"condition between parent/child tables on "
|
|
"relationship %s - there are no foreign keys "
|
|
"linking these tables via secondary table '%s'. "
|
|
"Ensure that referencing columns are associated "
|
|
"with a ForeignKey or ForeignKeyConstraint, or "
|
|
"specify 'primaryjoin' and 'secondaryjoin' "
|
|
"expressions." % (self.prop, self.secondary)
|
|
)
|
|
else:
|
|
raise sa_exc.NoForeignKeysError(
|
|
"Could not determine join "
|
|
"condition between parent/child tables on "
|
|
"relationship %s - there are no foreign keys "
|
|
"linking these tables. "
|
|
"Ensure that referencing columns are associated "
|
|
"with a ForeignKey or ForeignKeyConstraint, or "
|
|
"specify a 'primaryjoin' expression." % self.prop
|
|
)
|
|
except sa_exc.AmbiguousForeignKeysError:
|
|
if self.secondary is not None:
|
|
raise sa_exc.AmbiguousForeignKeysError(
|
|
"Could not determine join "
|
|
"condition between parent/child tables on "
|
|
"relationship %s - there are multiple foreign key "
|
|
"paths linking the tables via secondary table '%s'. "
|
|
"Specify the 'foreign_keys' "
|
|
"argument, providing a list of those columns which "
|
|
"should be counted as containing a foreign key "
|
|
"reference from the secondary table to each of the "
|
|
"parent and child tables." % (self.prop, self.secondary)
|
|
)
|
|
else:
|
|
raise sa_exc.AmbiguousForeignKeysError(
|
|
"Could not determine join "
|
|
"condition between parent/child tables on "
|
|
"relationship %s - there are multiple foreign key "
|
|
"paths linking the tables. Specify the "
|
|
"'foreign_keys' argument, providing a list of those "
|
|
"columns which should be counted as containing a "
|
|
"foreign key reference to the parent table." % self.prop
|
|
)
|
|
|
|
@property
|
|
def primaryjoin_minus_local(self):
|
|
return _deep_deannotate(self.primaryjoin, values=("local", "remote"))
|
|
|
|
@property
|
|
def secondaryjoin_minus_local(self):
|
|
return _deep_deannotate(self.secondaryjoin, values=("local", "remote"))
|
|
|
|
@util.memoized_property
|
|
def primaryjoin_reverse_remote(self):
|
|
"""Return the primaryjoin condition suitable for the
|
|
"reverse" direction.
|
|
|
|
If the primaryjoin was delivered here with pre-existing
|
|
"remote" annotations, the local/remote annotations
|
|
are reversed. Otherwise, the local/remote annotations
|
|
are removed.
|
|
|
|
"""
|
|
if self._has_remote_annotations:
|
|
|
|
def replace(element):
|
|
if "remote" in element._annotations:
|
|
v = element._annotations.copy()
|
|
del v["remote"]
|
|
v["local"] = True
|
|
return element._with_annotations(v)
|
|
elif "local" in element._annotations:
|
|
v = element._annotations.copy()
|
|
del v["local"]
|
|
v["remote"] = True
|
|
return element._with_annotations(v)
|
|
|
|
return visitors.replacement_traverse(self.primaryjoin, {}, replace)
|
|
else:
|
|
if self._has_foreign_annotations:
|
|
# TODO: coverage
|
|
return _deep_deannotate(
|
|
self.primaryjoin, values=("local", "remote")
|
|
)
|
|
else:
|
|
return _deep_deannotate(self.primaryjoin)
|
|
|
|
def _has_annotation(self, clause, annotation):
|
|
for col in visitors.iterate(clause, {}):
|
|
if annotation in col._annotations:
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
@util.memoized_property
|
|
def _has_foreign_annotations(self):
|
|
return self._has_annotation(self.primaryjoin, "foreign")
|
|
|
|
@util.memoized_property
|
|
def _has_remote_annotations(self):
|
|
return self._has_annotation(self.primaryjoin, "remote")
|
|
|
|
def _annotate_fks(self):
|
|
"""Annotate the primaryjoin and secondaryjoin
|
|
structures with 'foreign' annotations marking columns
|
|
considered as foreign.
|
|
|
|
"""
|
|
if self._has_foreign_annotations:
|
|
return
|
|
|
|
if self.consider_as_foreign_keys:
|
|
self._annotate_from_fk_list()
|
|
else:
|
|
self._annotate_present_fks()
|
|
|
|
def _annotate_from_fk_list(self):
|
|
def check_fk(col):
|
|
if col in self.consider_as_foreign_keys:
|
|
return col._annotate({"foreign": True})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, check_fk
|
|
)
|
|
if self.secondaryjoin is not None:
|
|
self.secondaryjoin = visitors.replacement_traverse(
|
|
self.secondaryjoin, {}, check_fk
|
|
)
|
|
|
|
def _annotate_present_fks(self):
|
|
if self.secondary is not None:
|
|
secondarycols = util.column_set(self.secondary.c)
|
|
else:
|
|
secondarycols = set()
|
|
|
|
def is_foreign(a, b):
|
|
if isinstance(a, schema.Column) and isinstance(b, schema.Column):
|
|
if a.references(b):
|
|
return a
|
|
elif b.references(a):
|
|
return b
|
|
|
|
if secondarycols:
|
|
if a in secondarycols and b not in secondarycols:
|
|
return a
|
|
elif b in secondarycols and a not in secondarycols:
|
|
return b
|
|
|
|
def visit_binary(binary):
|
|
if not isinstance(
|
|
binary.left, sql.ColumnElement
|
|
) or not isinstance(binary.right, sql.ColumnElement):
|
|
return
|
|
|
|
if (
|
|
"foreign" not in binary.left._annotations
|
|
and "foreign" not in binary.right._annotations
|
|
):
|
|
col = is_foreign(binary.left, binary.right)
|
|
if col is not None:
|
|
if col.compare(binary.left):
|
|
binary.left = binary.left._annotate({"foreign": True})
|
|
elif col.compare(binary.right):
|
|
binary.right = binary.right._annotate(
|
|
{"foreign": True}
|
|
)
|
|
|
|
self.primaryjoin = visitors.cloned_traverse(
|
|
self.primaryjoin, {}, {"binary": visit_binary}
|
|
)
|
|
if self.secondaryjoin is not None:
|
|
self.secondaryjoin = visitors.cloned_traverse(
|
|
self.secondaryjoin, {}, {"binary": visit_binary}
|
|
)
|
|
|
|
def _refers_to_parent_table(self):
|
|
"""Return True if the join condition contains column
|
|
comparisons where both columns are in both tables.
|
|
|
|
"""
|
|
pt = self.parent_persist_selectable
|
|
mt = self.child_persist_selectable
|
|
result = [False]
|
|
|
|
def visit_binary(binary):
|
|
c, f = binary.left, binary.right
|
|
if (
|
|
isinstance(c, expression.ColumnClause)
|
|
and isinstance(f, expression.ColumnClause)
|
|
and pt.is_derived_from(c.table)
|
|
and pt.is_derived_from(f.table)
|
|
and mt.is_derived_from(c.table)
|
|
and mt.is_derived_from(f.table)
|
|
):
|
|
result[0] = True
|
|
|
|
visitors.traverse(self.primaryjoin, {}, {"binary": visit_binary})
|
|
return result[0]
|
|
|
|
def _tables_overlap(self):
|
|
"""Return True if parent/child tables have some overlap."""
|
|
|
|
return selectables_overlap(
|
|
self.parent_persist_selectable, self.child_persist_selectable
|
|
)
|
|
|
|
def _annotate_remote(self):
|
|
"""Annotate the primaryjoin and secondaryjoin
|
|
structures with 'remote' annotations marking columns
|
|
considered as part of the 'remote' side.
|
|
|
|
"""
|
|
if self._has_remote_annotations:
|
|
return
|
|
|
|
if self.secondary is not None:
|
|
self._annotate_remote_secondary()
|
|
elif self._local_remote_pairs or self._remote_side:
|
|
self._annotate_remote_from_args()
|
|
elif self._refers_to_parent_table():
|
|
self._annotate_selfref(
|
|
lambda col: "foreign" in col._annotations, False
|
|
)
|
|
elif self._tables_overlap():
|
|
self._annotate_remote_with_overlap()
|
|
else:
|
|
self._annotate_remote_distinct_selectables()
|
|
|
|
def _annotate_remote_secondary(self):
|
|
"""annotate 'remote' in primaryjoin, secondaryjoin
|
|
when 'secondary' is present.
|
|
|
|
"""
|
|
|
|
def repl(element):
|
|
if self.secondary.c.contains_column(element):
|
|
return element._annotate({"remote": True})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, repl
|
|
)
|
|
self.secondaryjoin = visitors.replacement_traverse(
|
|
self.secondaryjoin, {}, repl
|
|
)
|
|
|
|
def _annotate_selfref(self, fn, remote_side_given):
|
|
"""annotate 'remote' in primaryjoin, secondaryjoin
|
|
when the relationship is detected as self-referential.
|
|
|
|
"""
|
|
|
|
def visit_binary(binary):
|
|
equated = binary.left.compare(binary.right)
|
|
if isinstance(binary.left, expression.ColumnClause) and isinstance(
|
|
binary.right, expression.ColumnClause
|
|
):
|
|
# assume one to many - FKs are "remote"
|
|
if fn(binary.left):
|
|
binary.left = binary.left._annotate({"remote": True})
|
|
if fn(binary.right) and not equated:
|
|
binary.right = binary.right._annotate({"remote": True})
|
|
elif not remote_side_given:
|
|
self._warn_non_column_elements()
|
|
|
|
self.primaryjoin = visitors.cloned_traverse(
|
|
self.primaryjoin, {}, {"binary": visit_binary}
|
|
)
|
|
|
|
def _annotate_remote_from_args(self):
|
|
"""annotate 'remote' in primaryjoin, secondaryjoin
|
|
when the 'remote_side' or '_local_remote_pairs'
|
|
arguments are used.
|
|
|
|
"""
|
|
if self._local_remote_pairs:
|
|
if self._remote_side:
|
|
raise sa_exc.ArgumentError(
|
|
"remote_side argument is redundant "
|
|
"against more detailed _local_remote_side "
|
|
"argument."
|
|
)
|
|
|
|
remote_side = [r for (l, r) in self._local_remote_pairs]
|
|
else:
|
|
remote_side = self._remote_side
|
|
|
|
if self._refers_to_parent_table():
|
|
self._annotate_selfref(lambda col: col in remote_side, True)
|
|
else:
|
|
|
|
def repl(element):
|
|
if element in remote_side:
|
|
return element._annotate({"remote": True})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, repl
|
|
)
|
|
|
|
def _annotate_remote_with_overlap(self):
|
|
"""annotate 'remote' in primaryjoin, secondaryjoin
|
|
when the parent/child tables have some set of
|
|
tables in common, though is not a fully self-referential
|
|
relationship.
|
|
|
|
"""
|
|
|
|
def visit_binary(binary):
|
|
binary.left, binary.right = proc_left_right(
|
|
binary.left, binary.right
|
|
)
|
|
binary.right, binary.left = proc_left_right(
|
|
binary.right, binary.left
|
|
)
|
|
|
|
check_entities = (
|
|
self.prop is not None and self.prop.mapper is not self.prop.parent
|
|
)
|
|
|
|
def proc_left_right(left, right):
|
|
if isinstance(left, expression.ColumnClause) and isinstance(
|
|
right, expression.ColumnClause
|
|
):
|
|
if self.child_persist_selectable.c.contains_column(
|
|
right
|
|
) and self.parent_persist_selectable.c.contains_column(left):
|
|
right = right._annotate({"remote": True})
|
|
elif (
|
|
check_entities
|
|
and right._annotations.get("parentmapper") is self.prop.mapper
|
|
):
|
|
right = right._annotate({"remote": True})
|
|
elif (
|
|
check_entities
|
|
and left._annotations.get("parentmapper") is self.prop.mapper
|
|
):
|
|
left = left._annotate({"remote": True})
|
|
else:
|
|
self._warn_non_column_elements()
|
|
|
|
return left, right
|
|
|
|
self.primaryjoin = visitors.cloned_traverse(
|
|
self.primaryjoin, {}, {"binary": visit_binary}
|
|
)
|
|
|
|
def _annotate_remote_distinct_selectables(self):
|
|
"""annotate 'remote' in primaryjoin, secondaryjoin
|
|
when the parent/child tables are entirely
|
|
separate.
|
|
|
|
"""
|
|
|
|
def repl(element):
|
|
if self.child_persist_selectable.c.contains_column(element) and (
|
|
not self.parent_local_selectable.c.contains_column(element)
|
|
or self.child_local_selectable.c.contains_column(element)
|
|
):
|
|
return element._annotate({"remote": True})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, repl
|
|
)
|
|
|
|
def _warn_non_column_elements(self):
|
|
util.warn(
|
|
"Non-simple column elements in primary "
|
|
"join condition for property %s - consider using "
|
|
"remote() annotations to mark the remote side." % self.prop
|
|
)
|
|
|
|
def _annotate_local(self):
|
|
"""Annotate the primaryjoin and secondaryjoin
|
|
structures with 'local' annotations.
|
|
|
|
This annotates all column elements found
|
|
simultaneously in the parent table
|
|
and the join condition that don't have a
|
|
'remote' annotation set up from
|
|
_annotate_remote() or user-defined.
|
|
|
|
"""
|
|
if self._has_annotation(self.primaryjoin, "local"):
|
|
return
|
|
|
|
if self._local_remote_pairs:
|
|
local_side = util.column_set(
|
|
[l for (l, r) in self._local_remote_pairs]
|
|
)
|
|
else:
|
|
local_side = util.column_set(self.parent_persist_selectable.c)
|
|
|
|
def locals_(elem):
|
|
if "remote" not in elem._annotations and elem in local_side:
|
|
return elem._annotate({"local": True})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, locals_
|
|
)
|
|
|
|
def _annotate_parentmapper(self):
|
|
if self.prop is None:
|
|
return
|
|
|
|
def parentmappers_(elem):
|
|
if "remote" in elem._annotations:
|
|
return elem._annotate({"parentmapper": self.prop.mapper})
|
|
elif "local" in elem._annotations:
|
|
return elem._annotate({"parentmapper": self.prop.parent})
|
|
|
|
self.primaryjoin = visitors.replacement_traverse(
|
|
self.primaryjoin, {}, parentmappers_
|
|
)
|
|
|
|
def _check_remote_side(self):
|
|
if not self.local_remote_pairs:
|
|
raise sa_exc.ArgumentError(
|
|
"Relationship %s could "
|
|
"not determine any unambiguous local/remote column "
|
|
"pairs based on join condition and remote_side "
|
|
"arguments. "
|
|
"Consider using the remote() annotation to "
|
|
"accurately mark those elements of the join "
|
|
"condition that are on the remote side of "
|
|
"the relationship." % (self.prop,)
|
|
)
|
|
|
|
def _check_foreign_cols(self, join_condition, primary):
|
|
"""Check the foreign key columns collected and emit error
|
|
messages."""
|
|
|
|
can_sync = False
|
|
|
|
foreign_cols = self._gather_columns_with_annotation(
|
|
join_condition, "foreign"
|
|
)
|
|
|
|
has_foreign = bool(foreign_cols)
|
|
|
|
if primary:
|
|
can_sync = bool(self.synchronize_pairs)
|
|
else:
|
|
can_sync = bool(self.secondary_synchronize_pairs)
|
|
|
|
if (
|
|
self.support_sync
|
|
and can_sync
|
|
or (not self.support_sync and has_foreign)
|
|
):
|
|
return
|
|
|
|
# from here below is just determining the best error message
|
|
# to report. Check for a join condition using any operator
|
|
# (not just ==), perhaps they need to turn on "viewonly=True".
|
|
if self.support_sync and has_foreign and not can_sync:
|
|
err = (
|
|
"Could not locate any simple equality expressions "
|
|
"involving locally mapped foreign key columns for "
|
|
"%s join condition "
|
|
"'%s' on relationship %s."
|
|
% (
|
|
primary and "primary" or "secondary",
|
|
join_condition,
|
|
self.prop,
|
|
)
|
|
)
|
|
err += (
|
|
" Ensure that referencing columns are associated "
|
|
"with a ForeignKey or ForeignKeyConstraint, or are "
|
|
"annotated in the join condition with the foreign() "
|
|
"annotation. To allow comparison operators other than "
|
|
"'==', the relationship can be marked as viewonly=True."
|
|
)
|
|
|
|
raise sa_exc.ArgumentError(err)
|
|
else:
|
|
err = (
|
|
"Could not locate any relevant foreign key columns "
|
|
"for %s join condition '%s' on relationship %s."
|
|
% (
|
|
primary and "primary" or "secondary",
|
|
join_condition,
|
|
self.prop,
|
|
)
|
|
)
|
|
err += (
|
|
" Ensure that referencing columns are associated "
|
|
"with a ForeignKey or ForeignKeyConstraint, or are "
|
|
"annotated in the join condition with the foreign() "
|
|
"annotation."
|
|
)
|
|
raise sa_exc.ArgumentError(err)
|
|
|
|
def _determine_direction(self):
|
|
"""Determine if this relationship is one to many, many to one,
|
|
many to many.
|
|
|
|
"""
|
|
if self.secondaryjoin is not None:
|
|
self.direction = MANYTOMANY
|
|
else:
|
|
parentcols = util.column_set(self.parent_persist_selectable.c)
|
|
targetcols = util.column_set(self.child_persist_selectable.c)
|
|
|
|
# fk collection which suggests ONETOMANY.
|
|
onetomany_fk = targetcols.intersection(self.foreign_key_columns)
|
|
|
|
# fk collection which suggests MANYTOONE.
|
|
|
|
manytoone_fk = parentcols.intersection(self.foreign_key_columns)
|
|
|
|
if onetomany_fk and manytoone_fk:
|
|
# fks on both sides. test for overlap of local/remote
|
|
# with foreign key.
|
|
# we will gather columns directly from their annotations
|
|
# without deannotating, so that we can distinguish on a column
|
|
# that refers to itself.
|
|
|
|
# 1. columns that are both remote and FK suggest
|
|
# onetomany.
|
|
onetomany_local = self._gather_columns_with_annotation(
|
|
self.primaryjoin, "remote", "foreign"
|
|
)
|
|
|
|
# 2. columns that are FK but are not remote (e.g. local)
|
|
# suggest manytoone.
|
|
manytoone_local = set(
|
|
[
|
|
c
|
|
for c in self._gather_columns_with_annotation(
|
|
self.primaryjoin, "foreign"
|
|
)
|
|
if "remote" not in c._annotations
|
|
]
|
|
)
|
|
|
|
# 3. if both collections are present, remove columns that
|
|
# refer to themselves. This is for the case of
|
|
# and_(Me.id == Me.remote_id, Me.version == Me.version)
|
|
if onetomany_local and manytoone_local:
|
|
self_equated = self.remote_columns.intersection(
|
|
self.local_columns
|
|
)
|
|
onetomany_local = onetomany_local.difference(self_equated)
|
|
manytoone_local = manytoone_local.difference(self_equated)
|
|
|
|
# at this point, if only one or the other collection is
|
|
# present, we know the direction, otherwise it's still
|
|
# ambiguous.
|
|
|
|
if onetomany_local and not manytoone_local:
|
|
self.direction = ONETOMANY
|
|
elif manytoone_local and not onetomany_local:
|
|
self.direction = MANYTOONE
|
|
else:
|
|
raise sa_exc.ArgumentError(
|
|
"Can't determine relationship"
|
|
" direction for relationship '%s' - foreign "
|
|
"key columns within the join condition are present "
|
|
"in both the parent and the child's mapped tables. "
|
|
"Ensure that only those columns referring "
|
|
"to a parent column are marked as foreign, "
|
|
"either via the foreign() annotation or "
|
|
"via the foreign_keys argument." % self.prop
|
|
)
|
|
elif onetomany_fk:
|
|
self.direction = ONETOMANY
|
|
elif manytoone_fk:
|
|
self.direction = MANYTOONE
|
|
else:
|
|
raise sa_exc.ArgumentError(
|
|
"Can't determine relationship "
|
|
"direction for relationship '%s' - foreign "
|
|
"key columns are present in neither the parent "
|
|
"nor the child's mapped tables" % self.prop
|
|
)
|
|
|
|
def _deannotate_pairs(self, collection):
|
|
"""provide deannotation for the various lists of
|
|
pairs, so that using them in hashes doesn't incur
|
|
high-overhead __eq__() comparisons against
|
|
original columns mapped.
|
|
|
|
"""
|
|
return [(x._deannotate(), y._deannotate()) for x, y in collection]
|
|
|
|
def _setup_pairs(self):
|
|
sync_pairs = []
|
|
lrp = util.OrderedSet([])
|
|
secondary_sync_pairs = []
|
|
|
|
def go(joincond, collection):
|
|
def visit_binary(binary, left, right):
|
|
if (
|
|
"remote" in right._annotations
|
|
and "remote" not in left._annotations
|
|
and self.can_be_synced_fn(left)
|
|
):
|
|
lrp.add((left, right))
|
|
elif (
|
|
"remote" in left._annotations
|
|
and "remote" not in right._annotations
|
|
and self.can_be_synced_fn(right)
|
|
):
|
|
lrp.add((right, left))
|
|
if binary.operator is operators.eq and self.can_be_synced_fn(
|
|
left, right
|
|
):
|
|
if "foreign" in right._annotations:
|
|
collection.append((left, right))
|
|
elif "foreign" in left._annotations:
|
|
collection.append((right, left))
|
|
|
|
visit_binary_product(visit_binary, joincond)
|
|
|
|
for joincond, collection in [
|
|
(self.primaryjoin, sync_pairs),
|
|
(self.secondaryjoin, secondary_sync_pairs),
|
|
]:
|
|
if joincond is None:
|
|
continue
|
|
go(joincond, collection)
|
|
|
|
self.local_remote_pairs = self._deannotate_pairs(lrp)
|
|
self.synchronize_pairs = self._deannotate_pairs(sync_pairs)
|
|
self.secondary_synchronize_pairs = self._deannotate_pairs(
|
|
secondary_sync_pairs
|
|
)
|
|
|
|
_track_overlapping_sync_targets = weakref.WeakKeyDictionary()
|
|
|
|
def _warn_for_conflicting_sync_targets(self):
|
|
if not self.support_sync:
|
|
return
|
|
|
|
# we would like to detect if we are synchronizing any column
|
|
# pairs in conflict with another relationship that wishes to sync
|
|
# an entirely different column to the same target. This is a
|
|
# very rare edge case so we will try to minimize the memory/overhead
|
|
# impact of this check
|
|
for from_, to_ in [
|
|
(from_, to_) for (from_, to_) in self.synchronize_pairs
|
|
] + [
|
|
(from_, to_) for (from_, to_) in self.secondary_synchronize_pairs
|
|
]:
|
|
# save ourselves a ton of memory and overhead by only
|
|
# considering columns that are subject to a overlapping
|
|
# FK constraints at the core level. This condition can arise
|
|
# if multiple relationships overlap foreign() directly, but
|
|
# we're going to assume it's typically a ForeignKeyConstraint-
|
|
# level configuration that benefits from this warning.
|
|
if len(to_.foreign_keys) < 2:
|
|
continue
|
|
|
|
if to_ not in self._track_overlapping_sync_targets:
|
|
self._track_overlapping_sync_targets[
|
|
to_
|
|
] = weakref.WeakKeyDictionary({self.prop: from_})
|
|
else:
|
|
other_props = []
|
|
prop_to_from = self._track_overlapping_sync_targets[to_]
|
|
|
|
for pr, fr_ in prop_to_from.items():
|
|
if (
|
|
pr.mapper in mapperlib._mapper_registry
|
|
and (
|
|
self.prop._persists_for(pr.parent)
|
|
or pr._persists_for(self.prop.parent)
|
|
)
|
|
and fr_ is not from_
|
|
and pr not in self.prop._reverse_property
|
|
):
|
|
|
|
other_props.append((pr, fr_))
|
|
|
|
if other_props:
|
|
util.warn(
|
|
"relationship '%s' will copy column %s to column %s, "
|
|
"which conflicts with relationship(s): %s. "
|
|
"Consider applying "
|
|
"viewonly=True to read-only relationships, or provide "
|
|
"a primaryjoin condition marking writable columns "
|
|
"with the foreign() annotation."
|
|
% (
|
|
self.prop,
|
|
from_,
|
|
to_,
|
|
", ".join(
|
|
"'%s' (copies %s to %s)" % (pr, fr_, to_)
|
|
for (pr, fr_) in other_props
|
|
),
|
|
)
|
|
)
|
|
self._track_overlapping_sync_targets[to_][self.prop] = from_
|
|
|
|
@util.memoized_property
|
|
def remote_columns(self):
|
|
return self._gather_join_annotations("remote")
|
|
|
|
@util.memoized_property
|
|
def local_columns(self):
|
|
return self._gather_join_annotations("local")
|
|
|
|
@util.memoized_property
|
|
def foreign_key_columns(self):
|
|
return self._gather_join_annotations("foreign")
|
|
|
|
def _gather_join_annotations(self, annotation):
|
|
s = set(
|
|
self._gather_columns_with_annotation(self.primaryjoin, annotation)
|
|
)
|
|
if self.secondaryjoin is not None:
|
|
s.update(
|
|
self._gather_columns_with_annotation(
|
|
self.secondaryjoin, annotation
|
|
)
|
|
)
|
|
return {x._deannotate() for x in s}
|
|
|
|
def _gather_columns_with_annotation(self, clause, *annotation):
|
|
annotation = set(annotation)
|
|
return set(
|
|
[
|
|
col
|
|
for col in visitors.iterate(clause, {})
|
|
if annotation.issubset(col._annotations)
|
|
]
|
|
)
|
|
|
|
def join_targets(
|
|
self, source_selectable, dest_selectable, aliased, single_crit=None
|
|
):
|
|
"""Given a source and destination selectable, create a
|
|
join between them.
|
|
|
|
This takes into account aliasing the join clause
|
|
to reference the appropriate corresponding columns
|
|
in the target objects, as well as the extra child
|
|
criterion, equivalent column sets, etc.
|
|
|
|
"""
|
|
# place a barrier on the destination such that
|
|
# replacement traversals won't ever dig into it.
|
|
# its internal structure remains fixed
|
|
# regardless of context.
|
|
dest_selectable = _shallow_annotate(
|
|
dest_selectable, {"no_replacement_traverse": True}
|
|
)
|
|
|
|
primaryjoin, secondaryjoin, secondary = (
|
|
self.primaryjoin,
|
|
self.secondaryjoin,
|
|
self.secondary,
|
|
)
|
|
|
|
# adjust the join condition for single table inheritance,
|
|
# in the case that the join is to a subclass
|
|
# this is analogous to the
|
|
# "_adjust_for_single_table_inheritance()" method in Query.
|
|
|
|
if single_crit is not None:
|
|
if secondaryjoin is not None:
|
|
secondaryjoin = secondaryjoin & single_crit
|
|
else:
|
|
primaryjoin = primaryjoin & single_crit
|
|
|
|
if aliased:
|
|
if secondary is not None:
|
|
secondary = secondary.alias(flat=True)
|
|
primary_aliasizer = ClauseAdapter(
|
|
secondary, exclude_fn=_ColInAnnotations("local")
|
|
)
|
|
secondary_aliasizer = ClauseAdapter(
|
|
dest_selectable, equivalents=self.child_equivalents
|
|
).chain(primary_aliasizer)
|
|
if source_selectable is not None:
|
|
primary_aliasizer = ClauseAdapter(
|
|
secondary, exclude_fn=_ColInAnnotations("local")
|
|
).chain(
|
|
ClauseAdapter(
|
|
source_selectable,
|
|
equivalents=self.parent_equivalents,
|
|
)
|
|
)
|
|
|
|
secondaryjoin = secondary_aliasizer.traverse(secondaryjoin)
|
|
else:
|
|
primary_aliasizer = ClauseAdapter(
|
|
dest_selectable,
|
|
exclude_fn=_ColInAnnotations("local"),
|
|
equivalents=self.child_equivalents,
|
|
)
|
|
if source_selectable is not None:
|
|
primary_aliasizer.chain(
|
|
ClauseAdapter(
|
|
source_selectable,
|
|
exclude_fn=_ColInAnnotations("remote"),
|
|
equivalents=self.parent_equivalents,
|
|
)
|
|
)
|
|
secondary_aliasizer = None
|
|
|
|
primaryjoin = primary_aliasizer.traverse(primaryjoin)
|
|
target_adapter = secondary_aliasizer or primary_aliasizer
|
|
target_adapter.exclude_fn = None
|
|
else:
|
|
target_adapter = None
|
|
return (
|
|
primaryjoin,
|
|
secondaryjoin,
|
|
secondary,
|
|
target_adapter,
|
|
dest_selectable,
|
|
)
|
|
|
|
def create_lazy_clause(self, reverse_direction=False):
|
|
binds = util.column_dict()
|
|
equated_columns = util.column_dict()
|
|
|
|
has_secondary = self.secondaryjoin is not None
|
|
|
|
if has_secondary:
|
|
lookup = collections.defaultdict(list)
|
|
for l, r in self.local_remote_pairs:
|
|
lookup[l].append((l, r))
|
|
equated_columns[r] = l
|
|
elif not reverse_direction:
|
|
for l, r in self.local_remote_pairs:
|
|
equated_columns[r] = l
|
|
else:
|
|
for l, r in self.local_remote_pairs:
|
|
equated_columns[l] = r
|
|
|
|
def col_to_bind(col):
|
|
|
|
if (
|
|
(not reverse_direction and "local" in col._annotations)
|
|
or reverse_direction
|
|
and (
|
|
(has_secondary and col in lookup)
|
|
or (not has_secondary and "remote" in col._annotations)
|
|
)
|
|
):
|
|
if col not in binds:
|
|
binds[col] = sql.bindparam(
|
|
None, None, type_=col.type, unique=True
|
|
)
|
|
return binds[col]
|
|
return None
|
|
|
|
lazywhere = self.primaryjoin
|
|
if self.secondaryjoin is None or not reverse_direction:
|
|
lazywhere = visitors.replacement_traverse(
|
|
lazywhere, {}, col_to_bind
|
|
)
|
|
|
|
if self.secondaryjoin is not None:
|
|
secondaryjoin = self.secondaryjoin
|
|
if reverse_direction:
|
|
secondaryjoin = visitors.replacement_traverse(
|
|
secondaryjoin, {}, col_to_bind
|
|
)
|
|
lazywhere = sql.and_(lazywhere, secondaryjoin)
|
|
|
|
bind_to_col = {binds[col].key: col for col in binds}
|
|
|
|
return lazywhere, bind_to_col, equated_columns
|
|
|
|
|
|
class _ColInAnnotations(object):
|
|
"""Seralizable equivalent to:
|
|
|
|
lambda c: "name" in c._annotations
|
|
"""
|
|
|
|
def __init__(self, name):
|
|
self.name = name
|
|
|
|
def __call__(self, c):
|
|
return self.name in c._annotations
|