2647 lines
108 KiB
Python
2647 lines
108 KiB
Python
# orm/relationships.py
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# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: http://www.opensource.org/licenses/mit-license.php
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"""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 .. import sql, util, exc as sa_exc, schema, log
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from .util import CascadeOptions, _orm_annotate, _orm_deannotate
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from . import dependency
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from . import attributes
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from ..sql.util import (
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ClauseAdapter,
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join_condition, _shallow_annotate, visit_binary_product,
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_deep_deannotate, selectables_overlap
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)
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from ..sql import operators, expression, visitors
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from .interfaces import MANYTOMANY, MANYTOONE, ONETOMANY, StrategizedProperty, PropComparator
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from ..inspection import inspect
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from . import mapper as mapperlib
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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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.. versionadded:: 0.8
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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(expression._clause_element_as_expr(expr),
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{"remote": True})
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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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.. versionadded:: 0.8
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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(expression._clause_element_as_expr(expr),
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{"foreign": True})
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@log.class_logger
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@util.langhelpers.dependency_for("sqlalchemy.orm.properties")
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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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See also:
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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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def __init__(self, argument,
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secondary=None, 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, extension=None,
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viewonly=False, lazy=True,
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collection_class=None, passive_deletes=False,
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passive_updates=True, remote_side=None,
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enable_typechecks=True, join_depth=None,
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comparator_factory=None,
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single_parent=False, 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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strategy_class=None, _local_remote_pairs=None,
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query_class=None,
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info=None):
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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. The
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constructed class is an instance of :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, and
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is assumed to be after all mappings have been constructed. This can be
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used to resolve order-of-declaration and other dependency issues, such as
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if ``Child`` is declared below ``Parent`` in the same 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 :func:`.relationship`.
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These string arguments are converted into callables that evaluate
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the string as Python code, using the Declarative
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class-registry as a namespace. This allows the lookup of related
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classes to be automatic via their string name, and removes the need to
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import related classes at all into the local module space::
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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 reference
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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 the
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target of the relationship.
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:paramref:`~.relationship.argument` may also be passed as a callable function
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which is evaluated at mapper initialization time, and may be passed as a
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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 typically
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applied in the case where the intermediary :class:`.Table` is not
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otherwise exprssed in any direct class mapping. If the "secondary" table
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is also explicitly mapped elsewhere
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(e.g. as in :ref:`association_pattern`), one should consider applying
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the :paramref:`~.relationship.viewonly` flag so that this :func:`.relationship`
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is not used for persistence operations which may conflict with those
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of the association object pattern.
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.. seealso::
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:ref:`relationships_many_to_many` - Reference example of "many 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 many-to-many
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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 :paramref:`~.relationship.secondary`
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when composing association table relationships, allowing additional
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attributes to be specified on the association table.
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:ref:`composite_secondary_join` - a lesser-used pattern which in some
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cases can enable complex :func:`.relationship` SQL conditions
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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 :paramref:`~.relationship.backref`,
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except the complementing property is **not** created automatically,
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and instead must be configured explicitly on the other mapper. The
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complementing property should also indicate :paramref:`~.relationship.back_populates`
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to this relationship to 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 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` which
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provides custom SQL clause generation for comparison 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 innermost
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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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.. versionadded:: 0.8.3 - :paramref:`~.relationship.distinct_target_key`
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allows the
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subquery eager loader to apply a DISTINCT modifier to the
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innermost SELECT.
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.. versionchanged:: 0.9.0 - :paramref:`~.relationship.distinct_target_key`
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now defaults to ``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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.. deprecated:: 0.7 Please see :class:`.AttributeEvents`.
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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` conditition 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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.. versionchanged:: 0.8
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A multiple-foreign key join ambiguity can be resolved by
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setting the :paramref:`~.relationship.foreign_keys` parameter alone, without the
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need to explicitly set :paramref:`~.relationship.primaryjoin` as well.
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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 construct a non-standard
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join condition, which makes use of columns or expressions that do
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not normally refer to their "parent" column, such as a join condition
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expressed by a 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 callable function
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which is evaluated at mapper initialization time, and may be passed as a
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Python-evaluable string when using 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" columns
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within a :paramref:`~.relationship.primaryjoin` condition.
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.. versionadded:: 0.8
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The :func:`.foreign` annotation can also be applied
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directly to the :paramref:`~.relationship.primaryjoin` expression, which is an alternate,
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more specific system of describing which columns in a particular
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:paramref:`~.relationship.primaryjoin` should be considered "foreign".
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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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.. versionadded:: 0.8
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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 nullable,
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or when the reference is one-to-one or a collection that is guaranteed
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to have one or at least one entry.
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If the joined-eager load is chained onto an existing LEFT OUTER JOIN,
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``innerjoin=True`` will be bypassed and the join will continue to
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chain as LEFT OUTER JOIN so that the results don't change. As an alternative,
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specify the value ``"nested"``. This will instead nest the join
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on the right side, e.g. using the form "a LEFT OUTER JOIN (b JOIN c)".
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.. versionadded:: 0.9.4 Added ``innerjoin="nested"`` option to support
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nesting of eager "inner" joins.
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.. seealso::
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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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:paramref:`.joinedload.innerjoin` - loader option version
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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 first
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accessed, using a separate SELECT statement, or identity map
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fetch for simple many-to-one references.
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* ``immediate`` - items should be loaded as the parents are loaded,
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using a separate SELECT statement, or identity map fetch for
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simple many-to-one references.
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* ``joined`` - items should be loaded "eagerly" in the same query as
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that of the parent, using a JOIN or LEFT OUTER JOIN. Whether
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the join is "outer" or not is determined by the
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:paramref:`~.relationship.innerjoin` parameter.
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* ``subquery`` - items should be loaded "eagerly" as the parents are
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loaded, using one additional SQL statement, which issues a JOIN to a
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subquery of the original statement, for each collection requested.
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* ``noload`` - no loading should occur at any time. This is to
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support "write-only" attributes, or attributes which are
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populated in some manner specific to the application.
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* ``dynamic`` - the attribute will return a pre-configured
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:class:`.Query` object for all read
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operations, onto which further filtering operations can be
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applied before iterating the results. See
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the section :ref:`dynamic_relationship` for more details.
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* True - a synonym for 'select'
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* False - a synonym for 'joined'
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* None - a synonym for 'noload'
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|
|
|
.. seealso::
|
|
|
|
:doc:`/orm/loading` - Full documentation on relationship loader
|
|
configuration.
|
|
|
|
:ref:`dynamic_relationship` - detail on the ``dynamic`` option.
|
|
|
|
: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 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.
|
|
|
|
.. seealso::
|
|
|
|
:ref:`passive_deletes` - Introductory documentation
|
|
and examples.
|
|
|
|
:param passive_updates=True:
|
|
Indicates loading and INSERT/UPDATE/DELETE behavior when the
|
|
source of a foreign key value changes (i.e. an "on update"
|
|
cascade), which are typically the primary key columns of the
|
|
source row.
|
|
|
|
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. Note that with databases which enforce
|
|
referential integrity (i.e. PostgreSQL, MySQL with InnoDB tables),
|
|
ON UPDATE CASCADE is required for this operation. The
|
|
relationship() will update the value of the attribute on related
|
|
items which are locally present in the session during a flush.
|
|
|
|
When False, it is assumed that the database does not enforce
|
|
referential integrity and will not be issuing its own CASCADE
|
|
operation for an update. The relationship() will issue the
|
|
appropriate UPDATE statements to the database in response to the
|
|
change of a referenced key, and items locally present in the
|
|
session during a flush will also be refreshed.
|
|
|
|
This flag should probably be set to False if primary key changes
|
|
are expected and the database in use doesn't support CASCADE
|
|
(i.e. SQLite, MySQL MyISAM tables).
|
|
|
|
.. 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 this child object against the parent object, or in a
|
|
many-to-many relationship the join of the primary 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.
|
|
|
|
.. versionchanged:: 0.8
|
|
The :func:`.remote` annotation can also be applied
|
|
directly to the ``primaryjoin`` expression, which is an alternate,
|
|
more specific system of describing which columns in a particular
|
|
``primaryjoin`` should be considered "remote".
|
|
|
|
.. seealso::
|
|
|
|
:ref:`self_referential` - in-depth explaination 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.
|
|
|
|
|
|
"""
|
|
|
|
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
|
|
self.local_remote_pairs = _local_remote_pairs
|
|
self.extension = extension
|
|
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
|
|
|
|
if strategy_class:
|
|
self.strategy_class = strategy_class
|
|
else:
|
|
self.strategy_class = self._strategy_lookup(("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.
|
|
|
|
See also:
|
|
|
|
: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._parentmapper = 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._parentmapper,
|
|
adapt_to_entity=adapt_to_entity,
|
|
of_type=self._of_type)
|
|
|
|
@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 = inspect(self._of_type).mapper
|
|
else:
|
|
of_type = None
|
|
|
|
pj, sj, source, dest, \
|
|
secondary, target_adapter = self.property._create_joins(
|
|
source_selectable=adapt_from,
|
|
source_polymorphic=True,
|
|
of_type=of_type)
|
|
if sj is not None:
|
|
return pj & sj
|
|
else:
|
|
return pj
|
|
|
|
def of_type(self, cls):
|
|
"""Produce a construct that represents a particular 'subtype' of
|
|
attribute for the parent class.
|
|
|
|
Currently this is usable in conjunction with :meth:`.Query.join`
|
|
and :meth:`.Query.outerjoin`.
|
|
|
|
"""
|
|
return RelationshipProperty.Comparator(
|
|
self.property,
|
|
self._parentmapper,
|
|
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 colle"
|
|
"ction 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)
|
|
|
|
ex = sql.exists([1], crit, from_obj=dest).correlate_except(dest)
|
|
if secondary is not None:
|
|
ex = ex.correlate_except(secondary)
|
|
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):
|
|
o = state.obj() # strong ref
|
|
return sql.bindparam(x, unique=True, callable_=lambda: \
|
|
self.property.mapper._get_committed_attr_by_column(o, 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 sql.or_(*[x != None for x in
|
|
self.property._calculated_foreign_keys])
|
|
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 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 compare(self, op, value,
|
|
value_is_parent=False,
|
|
alias_secondary=True):
|
|
if op == operators.eq:
|
|
if value is None:
|
|
if self.uselist:
|
|
return ~sql.exists([1], self.primaryjoin)
|
|
else:
|
|
return self._optimized_compare(None,
|
|
value_is_parent=value_is_parent,
|
|
alias_secondary=alias_secondary)
|
|
else:
|
|
return self._optimized_compare(value,
|
|
value_is_parent=value_is_parent,
|
|
alias_secondary=alias_secondary)
|
|
else:
|
|
return op(self.comparator, value)
|
|
|
|
def _optimized_compare(self, value, value_is_parent=False,
|
|
adapt_source=None,
|
|
alias_secondary=True):
|
|
if value is not None:
|
|
value = attributes.instance_state(value)
|
|
return self._lazy_strategy.lazy_clause(value,
|
|
reverse_direction=not value_is_parent,
|
|
alias_secondary=alias_secondary,
|
|
adapt_source=adapt_source)
|
|
|
|
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):
|
|
|
|
if load:
|
|
for r in self._reverse_property:
|
|
if (source_state, r) in _recursive:
|
|
return
|
|
|
|
if not "merge" 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 CollectionAttrbiuteImpl 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)
|
|
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_iterable(dest_state,
|
|
dest_dict, dest_list)
|
|
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)
|
|
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 mapper(self):
|
|
"""Return the targeted :class:`.Mapper` for this
|
|
:class:`.RelationshipProperty`.
|
|
|
|
This is a lazy-initializing static attribute.
|
|
|
|
"""
|
|
if util.callable(self.argument) and \
|
|
not isinstance(self.argument, (type, mapperlib.Mapper)):
|
|
argument = self.argument()
|
|
else:
|
|
argument = self.argument
|
|
|
|
if isinstance(argument, type):
|
|
mapper_ = mapperlib.class_mapper(argument,
|
|
configure=False)
|
|
elif isinstance(self.argument, mapperlib.Mapper):
|
|
mapper_ = argument
|
|
else:
|
|
raise sa_exc.ArgumentError("relationship '%s' expects "
|
|
"a class or a mapper argument (received: %s)"
|
|
% (self.key, type(argument)))
|
|
return mapper_
|
|
|
|
@util.memoized_property
|
|
@util.deprecated("0.7", "Use .target")
|
|
def table(self):
|
|
"""Return the selectable linked to this
|
|
:class:`.RelationshipProperty` object's target
|
|
:class:`.Mapper`.
|
|
"""
|
|
return self.target
|
|
|
|
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()
|
|
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.mapper.mapped_table
|
|
|
|
|
|
def _setup_join_conditions(self):
|
|
self._join_condition = jc = JoinCondition(
|
|
parent_selectable=self.parent.mapped_table,
|
|
child_selectable=self.mapper.mapped_table,
|
|
parent_local_selectable=self.parent.local_table,
|
|
child_local_selectable=self.mapper.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.deannotated_primaryjoin
|
|
self.secondaryjoin = jc.deannotated_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 not self.is_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__))
|
|
|
|
# check for conflicting relationship() on superclass
|
|
if not self.parent.concrete:
|
|
for inheriting in self.parent.iterate_to_root():
|
|
if inheriting is not self.parent \
|
|
and inheriting.has_property(self.key):
|
|
util.warn("Warning: relationship '%s' on mapper "
|
|
"'%s' supersedes the same relationship "
|
|
"on inherited mapper '%s'; this can "
|
|
"cause dependency issues during flush"
|
|
% (self.key, self.parent, inheriting))
|
|
|
|
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 _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.mapped_table.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 not self.is_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()
|
|
|
|
check = set(mapper.iterate_to_root()).\
|
|
union(mapper.self_and_descendants)
|
|
for m in check:
|
|
if m.has_property(backref_key):
|
|
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=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:
|
|
if dest_polymorphic and self.mapper.with_polymorphic:
|
|
dest_selectable = self.mapper._with_polymorphic_selectable
|
|
aliased = True
|
|
else:
|
|
dest_selectable = self.mapper.mapped_table
|
|
|
|
if self._is_self_referential and source_selectable is None:
|
|
dest_selectable = dest_selectable.alias()
|
|
aliased = True
|
|
else:
|
|
aliased = True
|
|
|
|
dest_mapper = of_type 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.mapper.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_selectable,
|
|
child_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_selectable = parent_selectable
|
|
self.parent_local_selectable = parent_local_selectable
|
|
self.child_selectable = child_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._annotate_fks()
|
|
self._annotate_remote()
|
|
self._annotate_local()
|
|
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 _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_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_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_selectable,
|
|
self.child_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_selectable
|
|
mt = self.child_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_selectable, self.child_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)
|
|
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):
|
|
"""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})
|
|
else:
|
|
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)
|
|
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)
|
|
|
|
def proc_left_right(left, right):
|
|
if isinstance(left, expression.ColumnClause) and \
|
|
isinstance(right, expression.ColumnClause):
|
|
if self.child_selectable.c.contains_column(right) and \
|
|
self.parent_selectable.c.contains_column(left):
|
|
right = right._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_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_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 _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_selectable.c)
|
|
targetcols = util.column_set(self.child_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
|
|
self_equated = self.remote_columns.intersection(
|
|
self.local_columns
|
|
)
|
|
onetomany_local = self.remote_columns.\
|
|
intersection(self.foreign_key_columns).\
|
|
difference(self_equated)
|
|
manytoone_local = self.local_columns.\
|
|
intersection(self.foreign_key_columns).\
|
|
difference(self_equated)
|
|
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)
|
|
|
|
@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")
|
|
|
|
@util.memoized_property
|
|
def deannotated_primaryjoin(self):
|
|
return _deep_deannotate(self.primaryjoin)
|
|
|
|
@util.memoized_property
|
|
def deannotated_secondaryjoin(self):
|
|
if self.secondaryjoin is not None:
|
|
return _deep_deannotate(self.secondaryjoin)
|
|
else:
|
|
return None
|
|
|
|
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 set([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)
|
|
secondary_aliasizer = \
|
|
ClauseAdapter(dest_selectable,
|
|
equivalents=self.child_equivalents).\
|
|
chain(primary_aliasizer)
|
|
if source_selectable is not None:
|
|
primary_aliasizer = \
|
|
ClauseAdapter(secondary).\
|
|
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()
|
|
lookup = util.column_dict()
|
|
equated_columns = util.column_dict()
|
|
being_replaced = set()
|
|
|
|
if reverse_direction and self.secondaryjoin is None:
|
|
for l, r in self.local_remote_pairs:
|
|
_list = lookup.setdefault(r, [])
|
|
_list.append((r, l))
|
|
equated_columns[l] = r
|
|
else:
|
|
# replace all "local side" columns, which is
|
|
# anything that isn't marked "remote"
|
|
being_replaced.update(self.local_columns)
|
|
for l, r in self.local_remote_pairs:
|
|
_list = lookup.setdefault(l, [])
|
|
_list.append((l, r))
|
|
equated_columns[r] = l
|
|
|
|
def col_to_bind(col):
|
|
if col in being_replaced or col in lookup:
|
|
if col in lookup:
|
|
for tobind, equated in lookup[col]:
|
|
if equated in binds:
|
|
return None
|
|
else:
|
|
assert not reverse_direction
|
|
if col not in binds:
|
|
binds[col] = sql.bindparam(
|
|
None, None, type_=col.type, unique=True)
|
|
return binds[col]
|
|
return None
|
|
|
|
lazywhere = self.deannotated_primaryjoin
|
|
|
|
if self.deannotated_secondaryjoin is None or not reverse_direction:
|
|
lazywhere = visitors.replacement_traverse(
|
|
lazywhere, {}, col_to_bind)
|
|
|
|
if self.deannotated_secondaryjoin is not None:
|
|
secondaryjoin = self.deannotated_secondaryjoin
|
|
if reverse_direction:
|
|
secondaryjoin = visitors.replacement_traverse(
|
|
secondaryjoin, {}, col_to_bind)
|
|
lazywhere = sql.and_(lazywhere, secondaryjoin)
|
|
|
|
bind_to_col = dict((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
|