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# orm/relationships.py
# Copyright (C) 2005-2024 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: https://www.opensource.org/licenses/mit-license.php
"""Heuristics related to join conditions as used in
:func:`_orm.relationship`.
Provides the :class:`.JoinCondition` object, which encapsulates
SQL annotation and aliasing behavior focused on the `primaryjoin`
and `secondaryjoin` aspects of :func:`_orm.relationship`.
"""
from __future__ import annotations
import collections
from collections import abc
import dataclasses
import inspect as _py_inspect
import itertools
import re
import typing
from typing import Any
from typing import Callable
from typing import cast
from typing import Collection
from typing import Dict
from typing import FrozenSet
from typing import Generic
from typing import Iterable
from typing import Iterator
from typing import List
from typing import NamedTuple
from typing import NoReturn
from typing import Optional
from typing import Sequence
from typing import Set
from typing import Tuple
from typing import Type
from typing import TypeVar
from typing import Union
import weakref
from . import attributes
from . import strategy_options
from ._typing import insp_is_aliased_class
from ._typing import is_has_collection_adapter
from .base import _DeclarativeMapped
from .base import _is_mapped_class
from .base import class_mapper
from .base import DynamicMapped
from .base import LoaderCallableStatus
from .base import PassiveFlag
from .base import state_str
from .base import WriteOnlyMapped
from .interfaces import _AttributeOptions
from .interfaces import _IntrospectsAnnotations
from .interfaces import MANYTOMANY
from .interfaces import MANYTOONE
from .interfaces import ONETOMANY
from .interfaces import PropComparator
from .interfaces import RelationshipDirection
from .interfaces import StrategizedProperty
from .util import _orm_annotate
from .util import _orm_deannotate
from .util import CascadeOptions
from .. import exc as sa_exc
from .. import Exists
from .. import log
from .. import schema
from .. import sql
from .. import util
from ..inspection import inspect
from ..sql import coercions
from ..sql import expression
from ..sql import operators
from ..sql import roles
from ..sql import visitors
from ..sql._typing import _ColumnExpressionArgument
from ..sql._typing import _HasClauseElement
from ..sql.annotation import _safe_annotate
from ..sql.elements import ColumnClause
from ..sql.elements import ColumnElement
from ..sql.util import _deep_annotate
from ..sql.util import _deep_deannotate
from ..sql.util import _shallow_annotate
from ..sql.util import adapt_criterion_to_null
from ..sql.util import ClauseAdapter
from ..sql.util import join_condition
from ..sql.util import selectables_overlap
from ..sql.util import visit_binary_product
from ..util.typing import de_optionalize_union_types
from ..util.typing import Literal
from ..util.typing import resolve_name_to_real_class_name
if typing.TYPE_CHECKING:
from ._typing import _EntityType
from ._typing import _ExternalEntityType
from ._typing import _IdentityKeyType
from ._typing import _InstanceDict
from ._typing import _InternalEntityType
from ._typing import _O
from ._typing import _RegistryType
from .base import Mapped
from .clsregistry import _class_resolver
from .clsregistry import _ModNS
from .decl_base import _ClassScanMapperConfig
from .dependency import DependencyProcessor
from .mapper import Mapper
from .query import Query
from .session import Session
from .state import InstanceState
from .strategies import LazyLoader
from .util import AliasedClass
from .util import AliasedInsp
from ..sql._typing import _CoreAdapterProto
from ..sql._typing import _EquivalentColumnMap
from ..sql._typing import _InfoType
from ..sql.annotation import _AnnotationDict
from ..sql.annotation import SupportsAnnotations
from ..sql.elements import BinaryExpression
from ..sql.elements import BindParameter
from ..sql.elements import ClauseElement
from ..sql.schema import Table
from ..sql.selectable import FromClause
from ..util.typing import _AnnotationScanType
from ..util.typing import RODescriptorReference
_T = TypeVar("_T", bound=Any)
_T1 = TypeVar("_T1", bound=Any)
_T2 = TypeVar("_T2", bound=Any)
_PT = TypeVar("_PT", bound=Any)
_PT2 = TypeVar("_PT2", bound=Any)
_RelationshipArgumentType = Union[
str,
Type[_T],
Callable[[], Type[_T]],
"Mapper[_T]",
"AliasedClass[_T]",
Callable[[], "Mapper[_T]"],
Callable[[], "AliasedClass[_T]"],
]
_LazyLoadArgumentType = Literal[
"select",
"joined",
"selectin",
"subquery",
"raise",
"raise_on_sql",
"noload",
"immediate",
"write_only",
"dynamic",
True,
False,
None,
]
_RelationshipJoinConditionArgument = Union[
str, _ColumnExpressionArgument[bool]
]
_RelationshipSecondaryArgument = Union[
"FromClause", str, Callable[[], "FromClause"]
]
_ORMOrderByArgument = Union[
Literal[False],
str,
_ColumnExpressionArgument[Any],
Callable[[], _ColumnExpressionArgument[Any]],
Callable[[], Iterable[_ColumnExpressionArgument[Any]]],
Iterable[Union[str, _ColumnExpressionArgument[Any]]],
]
ORMBackrefArgument = Union[str, Tuple[str, Dict[str, Any]]]
_ORMColCollectionElement = Union[
ColumnClause[Any],
_HasClauseElement[Any],
roles.DMLColumnRole,
"Mapped[Any]",
]
_ORMColCollectionArgument = Union[
str,
Sequence[_ORMColCollectionElement],
Callable[[], Sequence[_ORMColCollectionElement]],
Callable[[], _ORMColCollectionElement],
_ORMColCollectionElement,
]
_CEA = TypeVar("_CEA", bound=_ColumnExpressionArgument[Any])
_CE = TypeVar("_CE", bound="ColumnElement[Any]")
_ColumnPairIterable = Iterable[Tuple[ColumnElement[Any], ColumnElement[Any]]]
_ColumnPairs = Sequence[Tuple[ColumnElement[Any], ColumnElement[Any]]]
_MutableColumnPairs = List[Tuple[ColumnElement[Any], ColumnElement[Any]]]
def remote(expr: _CEA) -> _CEA:
"""Annotate a portion of a primaryjoin expression
with a 'remote' annotation.
See the section :ref:`relationship_custom_foreign` for a
description of use.
.. seealso::
:ref:`relationship_custom_foreign`
:func:`.foreign`
"""
return _annotate_columns( # type: ignore
coercions.expect(roles.ColumnArgumentRole, expr), {"remote": True}
)
def foreign(expr: _CEA) -> _CEA:
"""Annotate a portion of a primaryjoin expression
with a 'foreign' annotation.
See the section :ref:`relationship_custom_foreign` for a
description of use.
.. seealso::
:ref:`relationship_custom_foreign`
:func:`.remote`
"""
return _annotate_columns( # type: ignore
coercions.expect(roles.ColumnArgumentRole, expr), {"foreign": True}
)
@dataclasses.dataclass
class _RelationshipArg(Generic[_T1, _T2]):
"""stores a user-defined parameter value that must be resolved and
parsed later at mapper configuration time.
"""
__slots__ = "name", "argument", "resolved"
name: str
argument: _T1
resolved: Optional[_T2]
def _is_populated(self) -> bool:
return self.argument is not None
def _resolve_against_registry(
self, clsregistry_resolver: Callable[[str, bool], _class_resolver]
) -> None:
attr_value = self.argument
if isinstance(attr_value, str):
self.resolved = clsregistry_resolver(
attr_value, self.name == "secondary"
)()
elif callable(attr_value) and not _is_mapped_class(attr_value):
self.resolved = attr_value()
else:
self.resolved = attr_value
_RelationshipOrderByArg = Union[Literal[False], Tuple[ColumnElement[Any], ...]]
class _RelationshipArgs(NamedTuple):
"""stores user-passed parameters that are resolved at mapper configuration
time.
"""
secondary: _RelationshipArg[
Optional[_RelationshipSecondaryArgument],
Optional[FromClause],
]
primaryjoin: _RelationshipArg[
Optional[_RelationshipJoinConditionArgument],
Optional[ColumnElement[Any]],
]
secondaryjoin: _RelationshipArg[
Optional[_RelationshipJoinConditionArgument],
Optional[ColumnElement[Any]],
]
order_by: _RelationshipArg[_ORMOrderByArgument, _RelationshipOrderByArg]
foreign_keys: _RelationshipArg[
Optional[_ORMColCollectionArgument], Set[ColumnElement[Any]]
]
remote_side: _RelationshipArg[
Optional[_ORMColCollectionArgument], Set[ColumnElement[Any]]
]
@log.class_logger
class RelationshipProperty(
_IntrospectsAnnotations, StrategizedProperty[_T], log.Identified
):
"""Describes an object property that holds a single item or list
of items that correspond to a related database table.
Public constructor is the :func:`_orm.relationship` function.
.. seealso::
:ref:`relationship_config_toplevel`
"""
strategy_wildcard_key = strategy_options._RELATIONSHIP_TOKEN
inherit_cache = True
""":meta private:"""
_links_to_entity = True
_is_relationship = True
_overlaps: Sequence[str]
_lazy_strategy: LazyLoader
_persistence_only = dict(
passive_deletes=False,
passive_updates=True,
enable_typechecks=True,
active_history=False,
cascade_backrefs=False,
)
_dependency_processor: Optional[DependencyProcessor] = None
primaryjoin: ColumnElement[bool]
secondaryjoin: Optional[ColumnElement[bool]]
secondary: Optional[FromClause]
_join_condition: JoinCondition
order_by: _RelationshipOrderByArg
_user_defined_foreign_keys: Set[ColumnElement[Any]]
_calculated_foreign_keys: Set[ColumnElement[Any]]
remote_side: Set[ColumnElement[Any]]
local_columns: Set[ColumnElement[Any]]
synchronize_pairs: _ColumnPairs
secondary_synchronize_pairs: Optional[_ColumnPairs]
local_remote_pairs: Optional[_ColumnPairs]
direction: RelationshipDirection
_init_args: _RelationshipArgs
def __init__(
self,
argument: Optional[_RelationshipArgumentType[_T]] = None,
secondary: Optional[_RelationshipSecondaryArgument] = None,
*,
uselist: Optional[bool] = None,
collection_class: Optional[
Union[Type[Collection[Any]], Callable[[], Collection[Any]]]
] = None,
primaryjoin: Optional[_RelationshipJoinConditionArgument] = None,
secondaryjoin: Optional[_RelationshipJoinConditionArgument] = None,
back_populates: Optional[str] = None,
order_by: _ORMOrderByArgument = False,
backref: Optional[ORMBackrefArgument] = None,
overlaps: Optional[str] = None,
post_update: bool = False,
cascade: str = "save-update, merge",
viewonly: bool = False,
attribute_options: Optional[_AttributeOptions] = None,
lazy: _LazyLoadArgumentType = "select",
passive_deletes: Union[Literal["all"], bool] = False,
passive_updates: bool = True,
active_history: bool = False,
enable_typechecks: bool = True,
foreign_keys: Optional[_ORMColCollectionArgument] = None,
remote_side: Optional[_ORMColCollectionArgument] = None,
join_depth: Optional[int] = None,
comparator_factory: Optional[
Type[RelationshipProperty.Comparator[Any]]
] = None,
single_parent: bool = False,
innerjoin: bool = False,
distinct_target_key: Optional[bool] = None,
load_on_pending: bool = False,
query_class: Optional[Type[Query[Any]]] = None,
info: Optional[_InfoType] = None,
omit_join: Literal[None, False] = None,
sync_backref: Optional[bool] = None,
doc: Optional[str] = None,
bake_queries: Literal[True] = True,
cascade_backrefs: Literal[False] = False,
_local_remote_pairs: Optional[_ColumnPairs] = None,
_legacy_inactive_history_style: bool = False,
):
super().__init__(attribute_options=attribute_options)
self.uselist = uselist
self.argument = argument
self._init_args = _RelationshipArgs(
_RelationshipArg("secondary", secondary, None),
_RelationshipArg("primaryjoin", primaryjoin, None),
_RelationshipArg("secondaryjoin", secondaryjoin, None),
_RelationshipArg("order_by", order_by, None),
_RelationshipArg("foreign_keys", foreign_keys, None),
_RelationshipArg("remote_side", remote_side, None),
)
self.post_update = post_update
self.viewonly = viewonly
if viewonly:
self._warn_for_persistence_only_flags(
passive_deletes=passive_deletes,
passive_updates=passive_updates,
enable_typechecks=enable_typechecks,
active_history=active_history,
cascade_backrefs=cascade_backrefs,
)
if viewonly and sync_backref:
raise sa_exc.ArgumentError(
"sync_backref and viewonly cannot both be True"
)
self.sync_backref = sync_backref
self.lazy = lazy
self.single_parent = single_parent
self.collection_class = collection_class
self.passive_deletes = passive_deletes
if cascade_backrefs:
raise sa_exc.ArgumentError(
"The 'cascade_backrefs' parameter passed to "
"relationship() may only be set to False."
)
self.passive_updates = passive_updates
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._legacy_inactive_history_style = _legacy_inactive_history_style
self.join_depth = join_depth
if omit_join:
util.warn(
"setting omit_join to True is not supported; selectin "
"loading of this relationship may not work correctly if this "
"flag is set explicitly. omit_join optimization is "
"automatically detected for conditions under which it is "
"supported."
)
self.omit_join = omit_join
self.local_remote_pairs = _local_remote_pairs
self.load_on_pending = load_on_pending
self.comparator_factory = (
comparator_factory or RelationshipProperty.Comparator
)
util.set_creation_order(self)
if info is not None:
self.info.update(info)
self.strategy_key = (("lazy", self.lazy),)
self._reverse_property: Set[RelationshipProperty[Any]] = set()
if overlaps:
self._overlaps = set(re.split(r"\s*,\s*", overlaps)) # type: ignore # noqa: E501
else:
self._overlaps = ()
# mypy ignoring the @property setter
self.cascade = cascade # type: ignore
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 _warn_for_persistence_only_flags(self, **kw: Any) -> None:
for k, v in kw.items():
if v != self._persistence_only[k]:
# we are warning here rather than warn deprecated as this is a
# configuration mistake, and Python shows regular warnings more
# aggressively than deprecation warnings by default. Unlike the
# case of setting viewonly with cascade, the settings being
# warned about here are not actively doing the wrong thing
# against viewonly=True, so it is not as urgent to have these
# raise an error.
util.warn(
"Setting %s on relationship() while also "
"setting viewonly=True does not make sense, as a "
"viewonly=True relationship does not perform persistence "
"operations. This configuration may raise an error "
"in a future release." % (k,)
)
def instrument_class(self, mapper: Mapper[Any]) -> None:
attributes.register_descriptor(
mapper.class_,
self.key,
comparator=self.comparator_factory(self, mapper),
parententity=mapper,
doc=self.doc,
)
class Comparator(util.MemoizedSlots, PropComparator[_PT]):
"""Produce boolean, comparison, and other operators for
:class:`.RelationshipProperty` attributes.
See the documentation for :class:`.PropComparator` for a brief
overview of ORM level operator definition.
.. seealso::
:class:`.PropComparator`
:class:`.ColumnProperty.Comparator`
:class:`.ColumnOperators`
:ref:`types_operators`
:attr:`.TypeEngine.comparator_factory`
"""
__slots__ = (
"entity",
"mapper",
"property",
"_of_type",
"_extra_criteria",
)
prop: RODescriptorReference[RelationshipProperty[_PT]]
_of_type: Optional[_EntityType[_PT]]
def __init__(
self,
prop: RelationshipProperty[_PT],
parentmapper: _InternalEntityType[Any],
adapt_to_entity: Optional[AliasedInsp[Any]] = None,
of_type: Optional[_EntityType[_PT]] = None,
extra_criteria: Tuple[ColumnElement[bool], ...] = (),
):
"""Construction of :class:`.RelationshipProperty.Comparator`
is internal to the ORM's attribute mechanics.
"""
self.prop = prop
self._parententity = parentmapper
self._adapt_to_entity = adapt_to_entity
if of_type:
self._of_type = of_type
else:
self._of_type = None
self._extra_criteria = extra_criteria
def adapt_to_entity(
self, adapt_to_entity: AliasedInsp[Any]
) -> RelationshipProperty.Comparator[Any]:
return self.__class__(
self.prop,
self._parententity,
adapt_to_entity=adapt_to_entity,
of_type=self._of_type,
)
entity: _InternalEntityType[_PT]
"""The target entity referred to by this
:class:`.RelationshipProperty.Comparator`.
This is either a :class:`_orm.Mapper` or :class:`.AliasedInsp`
object.
This is the "target" or "remote" side of the
:func:`_orm.relationship`.
"""
mapper: Mapper[_PT]
"""The target :class:`_orm.Mapper` referred to by this
:class:`.RelationshipProperty.Comparator`.
This is the "target" or "remote" side of the
:func:`_orm.relationship`.
"""
def _memoized_attr_entity(self) -> _InternalEntityType[_PT]:
if self._of_type:
return inspect(self._of_type) # type: ignore
else:
return self.prop.entity
def _memoized_attr_mapper(self) -> Mapper[_PT]:
return self.entity.mapper
def _source_selectable(self) -> FromClause:
if self._adapt_to_entity:
return self._adapt_to_entity.selectable
else:
return self.property.parent._with_polymorphic_selectable
def __clause_element__(self) -> ColumnElement[bool]:
adapt_from = self._source_selectable()
if self._of_type:
of_type_entity = inspect(self._of_type)
else:
of_type_entity = None
(
pj,
sj,
source,
dest,
secondary,
target_adapter,
) = self.prop._create_joins(
source_selectable=adapt_from,
source_polymorphic=True,
of_type_entity=of_type_entity,
alias_secondary=True,
extra_criteria=self._extra_criteria,
)
if sj is not None:
return pj & sj
else:
return pj
def of_type(self, class_: _EntityType[Any]) -> PropComparator[_PT]:
r"""Redefine this object in terms of a polymorphic subclass.
See :meth:`.PropComparator.of_type` for an example.
"""
return RelationshipProperty.Comparator(
self.prop,
self._parententity,
adapt_to_entity=self._adapt_to_entity,
of_type=class_,
extra_criteria=self._extra_criteria,
)
def and_(
self, *criteria: _ColumnExpressionArgument[bool]
) -> PropComparator[Any]:
"""Add AND criteria.
See :meth:`.PropComparator.and_` for an example.
.. versionadded:: 1.4
"""
exprs = tuple(
coercions.expect(roles.WhereHavingRole, clause)
for clause in util.coerce_generator_arg(criteria)
)
return RelationshipProperty.Comparator(
self.prop,
self._parententity,
adapt_to_entity=self._adapt_to_entity,
of_type=self._of_type,
extra_criteria=self._extra_criteria + exprs,
)
def in_(self, other: Any) -> NoReturn:
"""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."
)
# https://github.com/python/mypy/issues/4266
__hash__ = None # type: ignore
def __eq__(self, other: Any) -> ColumnElement[bool]: # type: ignore[override] # noqa: E501
"""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:`~.Relationship.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:`~.Relationship.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 other is None or isinstance(other, expression.Null):
if self.property.direction in [ONETOMANY, MANYTOMANY]:
return ~self._criterion_exists()
else:
return _orm_annotate(
self.property._optimized_compare(
None, adapt_source=self.adapter
)
)
elif self.property.uselist:
raise sa_exc.InvalidRequestError(
"Can't compare a collection to an object or collection; "
"use contains() to test for membership."
)
else:
return _orm_annotate(
self.property._optimized_compare(
other, adapt_source=self.adapter
)
)
def _criterion_exists(
self,
criterion: Optional[_ColumnExpressionArgument[bool]] = None,
**kwargs: Any,
) -> Exists:
where_criteria = (
coercions.expect(roles.WhereHavingRole, criterion)
if criterion is not None
else None
)
if getattr(self, "_of_type", None):
info: Optional[_InternalEntityType[Any]] = inspect(
self._of_type
)
assert info is not None
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._anonymous_fromclause()
single_crit = target_mapper._single_table_criterion
if single_crit is not None:
if where_criteria is not None:
where_criteria = single_crit & where_criteria
else:
where_criteria = 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_selectable=to_selectable,
source_selectable=source_selectable,
)
for k in kwargs:
crit = getattr(self.property.mapper.class_, k) == kwargs[k]
if where_criteria is None:
where_criteria = crit
else:
where_criteria = where_criteria & 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 (
where_criteria is not None
and target_adapter
and not is_aliased_class
):
# limit this adapter to annotated only?
where_criteria = target_adapter.traverse(where_criteria)
# 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 where_criteria is not None:
where_criteria = where_criteria._annotate(
{"no_replacement_traverse": True}
)
crit = j & sql.True_._ifnone(where_criteria)
if secondary is not None:
ex = (
sql.exists(1)
.where(crit)
.select_from(dest, secondary)
.correlate_except(dest, secondary)
)
else:
ex = (
sql.exists(1)
.where(crit)
.select_from(dest)
.correlate_except(dest)
)
return ex
def any(
self,
criterion: Optional[_ColumnExpressionArgument[bool]] = None,
**kwargs: Any,
) -> ColumnElement[bool]:
"""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:`~.Relationship.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:`~.Relationship.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:`~.Relationship.Comparator.any` is only
valid for collections, i.e. a :func:`_orm.relationship`
that has ``uselist=True``. For scalar references,
use :meth:`~.Relationship.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: Optional[_ColumnExpressionArgument[bool]] = None,
**kwargs: Any,
) -> ColumnElement[bool]:
"""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:`~.Relationship.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:`~.Relationship.Comparator.has` is only
valid for scalar references, i.e. a :func:`_orm.relationship`
that has ``uselist=False``. For collection references,
use :meth:`~.Relationship.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: _ColumnExpressionArgument[Any], **kwargs: Any
) -> ColumnElement[bool]:
"""Return a simple expression that tests a collection for
containment of a particular item.
:meth:`~.Relationship.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:`~.Relationship.Comparator.contains` is
very useful when used with simple one-to-many
operations.
For many-to-many operations, the behavior of
:meth:`~.Relationship.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:`~.Relationship.Comparator.contains`
will **not** work with many-to-many collections when
used in queries that move beyond simple AND
conjunctions, such as multiple
:meth:`~.Relationship.Comparator.contains`
expressions joined by OR. In such cases subqueries or
explicit "outer joins" will need to be used instead.
See :meth:`~.Relationship.Comparator.any` for
a less-performant alternative using EXISTS, or refer
to :meth:`_query.Query.outerjoin`
as well as :ref:`orm_queryguide_joins`
for more details on constructing outer joins.
kwargs may be ignored by this operator but are required for API
conformance.
"""
if not self.prop.uselist:
raise sa_exc.InvalidRequestError(
"'contains' not implemented for scalar "
"attributes. Use =="
)
clause = self.prop._optimized_compare(
other, adapt_source=self.adapter
)
if self.prop.secondaryjoin is not None:
clause.negation_clause = self.__negated_contains_or_equals(
other
)
return clause
def __negated_contains_or_equals(
self, other: Any
) -> ColumnElement[bool]:
if self.prop.direction == MANYTOONE:
state = attributes.instance_state(other)
def state_bindparam(
local_col: ColumnElement[Any],
state: InstanceState[Any],
remote_col: ColumnElement[Any],
) -> BindParameter[Any]:
dict_ = state.dict
return sql.bindparam(
local_col.key,
type_=local_col.type,
unique=True,
callable_=self.prop._get_attr_w_warn_on_none(
self.prop.mapper, state, dict_, remote_col
),
)
def adapt(col: _CE) -> _CE:
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: Any) -> ColumnElement[bool]: # type: ignore[override] # noqa: E501
"""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:`~.Relationship.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:`~.Relationship.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 other is None or isinstance(other, expression.Null):
if self.property.direction == MANYTOONE:
return _orm_annotate(
~self.property._optimized_compare(
None, adapt_source=self.adapter
)
)
else:
return self._criterion_exists()
elif self.property.uselist:
raise sa_exc.InvalidRequestError(
"Can't compare a collection"
" to an object or collection; use "
"contains() to test for membership."
)
else:
return _orm_annotate(self.__negated_contains_or_equals(other))
def _memoized_attr_property(self) -> RelationshipProperty[_PT]:
self.prop.parent._check_configure()
return self.prop
def _with_parent(
self,
instance: object,
alias_secondary: bool = True,
from_entity: Optional[_EntityType[Any]] = None,
) -> ColumnElement[bool]:
assert instance is not None
adapt_source: Optional[_CoreAdapterProto] = None
if from_entity is not None:
insp: Optional[_InternalEntityType[Any]] = inspect(from_entity)
assert insp is not None
if insp_is_aliased_class(insp):
adapt_source = insp._adapter.adapt_clause
return self._optimized_compare(
instance,
value_is_parent=True,
adapt_source=adapt_source,
alias_secondary=alias_secondary,
)
def _optimized_compare(
self,
state: Any,
value_is_parent: bool = False,
adapt_source: Optional[_CoreAdapterProto] = None,
alias_secondary: bool = True,
) -> ColumnElement[bool]:
if state is not None:
try:
state = inspect(state)
except sa_exc.NoInspectionAvailable:
state = None
if state is None or not getattr(state, "is_instance", False):
raise sa_exc.ArgumentError(
"Mapped instance expected for relationship "
"comparison to object. Classes, queries and other "
"SQL elements are not accepted in this context; for "
"comparison with a subquery, "
"use %s.has(**criteria)." % self
)
reverse_direction = not value_is_parent
if state is None:
return self._lazy_none_clause(
reverse_direction, adapt_source=adapt_source
)
if not reverse_direction:
criterion, bind_to_col = (
self._lazy_strategy._lazywhere,
self._lazy_strategy._bind_to_col,
)
else:
criterion, bind_to_col = (
self._lazy_strategy._rev_lazywhere,
self._lazy_strategy._rev_bind_to_col,
)
if reverse_direction:
mapper = self.mapper
else:
mapper = self.parent
dict_ = attributes.instance_dict(state.obj())
def visit_bindparam(bindparam: BindParameter[Any]) -> None:
if bindparam._identifying_key in bind_to_col:
bindparam.callable = self._get_attr_w_warn_on_none(
mapper,
state,
dict_,
bind_to_col[bindparam._identifying_key],
)
if self.secondary is not None and alias_secondary:
criterion = ClauseAdapter(
self.secondary._anonymous_fromclause()
).traverse(criterion)
criterion = visitors.cloned_traverse(
criterion, {}, {"bindparam": visit_bindparam}
)
if adapt_source:
criterion = adapt_source(criterion)
return criterion
def _get_attr_w_warn_on_none(
self,
mapper: Mapper[Any],
state: InstanceState[Any],
dict_: _InstanceDict,
column: ColumnElement[Any],
) -> Callable[[], Any]:
"""Create the callable that is used in a many-to-one expression.
E.g.::
u1 = s.query(User).get(5)
expr = Address.user == u1
Above, the SQL should be "address.user_id = 5". The callable
returned by this method produces the value "5" based on the identity
of ``u1``.
"""
# in this callable, we're trying to thread the needle through
# a wide variety of scenarios, including:
#
# * the object hasn't been flushed yet and there's no value for
# the attribute as of yet
#
# * the object hasn't been flushed yet but it has a user-defined
# value
#
# * the object has a value but it's expired and not locally present
#
# * the object has a value but it's expired and not locally present,
# and the object is also detached
#
# * The object hadn't been flushed yet, there was no value, but
# later, the object has been expired and detached, and *now*
# they're trying to evaluate it
#
# * the object had a value, but it was changed to a new value, and
# then expired
#
# * the object had a value, but it was changed to a new value, and
# then expired, then the object was detached
#
# * the object has a user-set value, but it's None and we don't do
# the comparison correctly for that so warn
#
prop = mapper.get_property_by_column(column)
# by invoking this method, InstanceState will track the last known
# value for this key each time the attribute is to be expired.
# this feature was added explicitly for use in this method.
state._track_last_known_value(prop.key)
lkv_fixed = state._last_known_values
def _go() -> Any:
assert lkv_fixed is not None
last_known = to_return = lkv_fixed[prop.key]
existing_is_available = (
last_known is not LoaderCallableStatus.NO_VALUE
)
# we support that the value may have changed. so here we
# try to get the most recent value including re-fetching.
# only if we can't get a value now due to detachment do we return
# the last known value
current_value = mapper._get_state_attr_by_column(
state,
dict_,
column,
passive=(
PassiveFlag.PASSIVE_OFF
if state.persistent
else PassiveFlag.PASSIVE_NO_FETCH ^ PassiveFlag.INIT_OK
),
)
if current_value is LoaderCallableStatus.NEVER_SET:
if not existing_is_available:
raise sa_exc.InvalidRequestError(
"Can't resolve value for column %s on object "
"%s; no value has been set for this column"
% (column, state_str(state))
)
elif current_value is LoaderCallableStatus.PASSIVE_NO_RESULT:
if not existing_is_available:
raise sa_exc.InvalidRequestError(
"Can't resolve value for column %s on object "
"%s; the object is detached and the value was "
"expired" % (column, state_str(state))
)
else:
to_return = current_value
if to_return is None:
util.warn(
"Got None for value of column %s; this is unsupported "
"for a relationship comparison and will not "
"currently produce an IS comparison "
"(but may in a future release)" % column
)
return to_return
return _go
def _lazy_none_clause(
self,
reverse_direction: bool = False,
adapt_source: Optional[_CoreAdapterProto] = None,
) -> ColumnElement[bool]:
if not reverse_direction:
criterion, bind_to_col = (
self._lazy_strategy._lazywhere,
self._lazy_strategy._bind_to_col,
)
else:
criterion, bind_to_col = (
self._lazy_strategy._rev_lazywhere,
self._lazy_strategy._rev_bind_to_col,
)
criterion = adapt_criterion_to_null(criterion, bind_to_col)
if adapt_source:
criterion = adapt_source(criterion)
return criterion
def __str__(self) -> str:
return str(self.parent.class_.__name__) + "." + self.key
def merge(
self,
session: Session,
source_state: InstanceState[Any],
source_dict: _InstanceDict,
dest_state: InstanceState[Any],
dest_dict: _InstanceDict,
load: bool,
_recursive: Dict[Any, object],
_resolve_conflict_map: Dict[_IdentityKeyType[Any], object],
) -> None:
if load:
for r in self._reverse_property:
if (source_state, r) in _recursive:
return
if "merge" not in self._cascade:
return
if self.key not in source_dict:
return
if self.uselist:
impl = source_state.get_impl(self.key)
assert is_has_collection_adapter(impl)
instances_iterable = impl.get_collection(source_state, source_dict)
# if this is a CollectionAttributeImpl, then empty should
# be False, otherwise "self.key in source_dict" should not be
# True
assert not instances_iterable.empty if impl.collection else True
if load:
# for a full merge, pre-load the destination collection,
# so that individual _merge of each item pulls from identity
# map for those already present.
# also assumes CollectionAttributeImpl behavior of loading
# "old" list in any case
dest_state.get_impl(self.key).get(
dest_state, dest_dict, passive=PassiveFlag.PASSIVE_MERGE
)
dest_list = []
for current in instances_iterable:
current_state = attributes.instance_state(current)
current_dict = attributes.instance_dict(current)
_recursive[(current_state, self)] = True
obj = session._merge(
current_state,
current_dict,
load=load,
_recursive=_recursive,
_resolve_conflict_map=_resolve_conflict_map,
)
if obj is not None:
dest_list.append(obj)
if not load:
coll = attributes.init_state_collection(
dest_state, dest_dict, self.key
)
for c in dest_list:
coll.append_without_event(c)
else:
dest_impl = dest_state.get_impl(self.key)
assert is_has_collection_adapter(dest_impl)
dest_impl.set(
dest_state,
dest_dict,
dest_list,
_adapt=False,
passive=PassiveFlag.PASSIVE_MERGE,
)
else:
current = source_dict[self.key]
if current is not None:
current_state = attributes.instance_state(current)
current_dict = attributes.instance_dict(current)
_recursive[(current_state, self)] = True
obj = session._merge(
current_state,
current_dict,
load=load,
_recursive=_recursive,
_resolve_conflict_map=_resolve_conflict_map,
)
else:
obj = None
if not load:
dest_dict[self.key] = obj
else:
dest_state.get_impl(self.key).set(
dest_state, dest_dict, obj, None
)
def _value_as_iterable(
self,
state: InstanceState[_O],
dict_: _InstanceDict,
key: str,
passive: PassiveFlag = PassiveFlag.PASSIVE_OFF,
) -> Sequence[Tuple[InstanceState[_O], _O]]:
"""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 LoaderCallableStatus.PASSIVE_NO_RESULT or x is None:
return []
elif is_has_collection_adapter(impl):
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_: str,
state: InstanceState[Any],
dict_: _InstanceDict,
visited_states: Set[InstanceState[Any]],
halt_on: Optional[Callable[[InstanceState[Any]], bool]] = None,
) -> Iterator[Tuple[Any, Mapper[Any], InstanceState[Any], _InstanceDict]]:
# assert type_ in self._cascade
# only actively lazy load on the 'delete' cascade
if type_ != "delete" or self.passive_deletes:
passive = PassiveFlag.PASSIVE_NO_INITIALIZE
else:
passive = PassiveFlag.PASSIVE_OFF | PassiveFlag.NO_RAISE
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
assert instance_state is not None
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
@property
def _effective_sync_backref(self) -> bool:
if self.viewonly:
return False
else:
return self.sync_backref is not False
@staticmethod
def _check_sync_backref(
rel_a: RelationshipProperty[Any], rel_b: RelationshipProperty[Any]
) -> None:
if rel_a.viewonly and rel_b.sync_backref:
raise sa_exc.InvalidRequestError(
"Relationship %s cannot specify sync_backref=True since %s "
"includes viewonly=True." % (rel_b, rel_a)
)
if (
rel_a.viewonly
and not rel_b.viewonly
and rel_b.sync_backref is not False
):
rel_b.sync_backref = False
def _add_reverse_property(self, key: str) -> None:
other = self.mapper.get_property(key, _configure_mappers=False)
if not isinstance(other, RelationshipProperty):
raise sa_exc.InvalidRequestError(
"back_populates on relationship '%s' refers to attribute '%s' "
"that is not a relationship. The back_populates parameter "
"should refer to the name of a relationship on the target "
"class." % (self, other)
)
# viewonly and sync_backref cases
# 1. self.viewonly==True and other.sync_backref==True -> error
# 2. self.viewonly==True and other.viewonly==False and
# other.sync_backref==None -> warn sync_backref=False, set to False
self._check_sync_backref(self, other)
# 3. other.viewonly==True and self.sync_backref==True -> error
# 4. other.viewonly==True and self.viewonly==False and
# self.sync_backref==None -> warn sync_backref=False, set to False
self._check_sync_backref(other, self)
self._reverse_property.add(other)
other._reverse_property.add(self)
other._setup_entity()
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 (
other._configure_started
and self.direction in (ONETOMANY, MANYTOONE)
and self.direction == other.direction
):
raise sa_exc.ArgumentError(
"%s and back-reference %s are "
"both of the same direction %r. Did you mean to "
"set remote_side on the many-to-one side ?"
% (other, self, self.direction)
)
@util.memoized_property
def entity(self) -> _InternalEntityType[_T]:
"""Return the target mapped entity, which is an inspect() of the
class or aliased class that is referenced by this
:class:`.RelationshipProperty`.
"""
self.parent._check_configure()
return self.entity
@util.memoized_property
def mapper(self) -> Mapper[_T]:
"""Return the targeted :class:`_orm.Mapper` for this
:class:`.RelationshipProperty`.
"""
return self.entity.mapper
def do_init(self) -> None:
self._check_conflicts()
self._process_dependent_arguments()
self._setup_entity()
self._setup_registry_dependencies()
self._setup_join_conditions()
self._check_cascade_settings(self._cascade)
self._post_init()
self._generate_backref()
self._join_condition._warn_for_conflicting_sync_targets()
super().do_init()
self._lazy_strategy = cast(
"LazyLoader", self._get_strategy((("lazy", "select"),))
)
def _setup_registry_dependencies(self) -> None:
self.parent.mapper.registry._set_depends_on(
self.entity.mapper.registry
)
def _process_dependent_arguments(self) -> None:
"""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.
init_args = self._init_args
for attr in (
"order_by",
"primaryjoin",
"secondaryjoin",
"secondary",
"foreign_keys",
"remote_side",
):
rel_arg = getattr(init_args, attr)
rel_arg._resolve_against_registry(self._clsregistry_resolvers[1])
# remove "annotations" which are present if mapped class
# descriptors are used to create the join expression.
for attr in "primaryjoin", "secondaryjoin":
rel_arg = getattr(init_args, attr)
val = rel_arg.resolved
if val is not None:
rel_arg.resolved = _orm_deannotate(
coercions.expect(
roles.ColumnArgumentRole, val, argname=attr
)
)
secondary = init_args.secondary.resolved
if secondary is not None and _is_mapped_class(secondary):
raise sa_exc.ArgumentError(
"secondary argument %s passed to to relationship() %s must "
"be a Table object or other FROM clause; can't send a mapped "
"class directly as rows in 'secondary' are persisted "
"independently of a class that is mapped "
"to that same table." % (secondary, self)
)
# ensure expressions in self.order_by, foreign_keys,
# remote_side are all columns, not strings.
if (
init_args.order_by.resolved is not False
and init_args.order_by.resolved is not None
):
self.order_by = tuple(
coercions.expect(
roles.ColumnArgumentRole, x, argname="order_by"
)
for x in util.to_list(init_args.order_by.resolved)
)
else:
self.order_by = False
self._user_defined_foreign_keys = util.column_set(
coercions.expect(
roles.ColumnArgumentRole, x, argname="foreign_keys"
)
for x in util.to_column_set(init_args.foreign_keys.resolved)
)
self.remote_side = util.column_set(
coercions.expect(
roles.ColumnArgumentRole, x, argname="remote_side"
)
for x in util.to_column_set(init_args.remote_side.resolved)
)
def declarative_scan(
self,
decl_scan: _ClassScanMapperConfig,
registry: _RegistryType,
cls: Type[Any],
originating_module: Optional[str],
key: str,
mapped_container: Optional[Type[Mapped[Any]]],
annotation: Optional[_AnnotationScanType],
extracted_mapped_annotation: Optional[_AnnotationScanType],
is_dataclass_field: bool,
) -> None:
argument = extracted_mapped_annotation
if extracted_mapped_annotation is None:
if self.argument is None:
self._raise_for_required(key, cls)
else:
return
argument = extracted_mapped_annotation
assert originating_module is not None
if mapped_container is not None:
is_write_only = issubclass(mapped_container, WriteOnlyMapped)
is_dynamic = issubclass(mapped_container, DynamicMapped)
if is_write_only:
self.lazy = "write_only"
self.strategy_key = (("lazy", self.lazy),)
elif is_dynamic:
self.lazy = "dynamic"
self.strategy_key = (("lazy", self.lazy),)
else:
is_write_only = is_dynamic = False
argument = de_optionalize_union_types(argument)
if hasattr(argument, "__origin__"):
arg_origin = argument.__origin__
if isinstance(arg_origin, type) and issubclass(
arg_origin, abc.Collection
):
if self.collection_class is None:
if _py_inspect.isabstract(arg_origin):
raise sa_exc.ArgumentError(
f"Collection annotation type {arg_origin} cannot "
"be instantiated; please provide an explicit "
"'collection_class' parameter "
"(e.g. list, set, etc.) to the "
"relationship() function to accompany this "
"annotation"
)
self.collection_class = arg_origin
elif not is_write_only and not is_dynamic:
self.uselist = False
if argument.__args__: # type: ignore
if isinstance(arg_origin, type) and issubclass(
arg_origin, typing.Mapping
):
type_arg = argument.__args__[-1] # type: ignore
else:
type_arg = argument.__args__[0] # type: ignore
if hasattr(type_arg, "__forward_arg__"):
str_argument = type_arg.__forward_arg__
argument = resolve_name_to_real_class_name(
str_argument, originating_module
)
else:
argument = type_arg
else:
raise sa_exc.ArgumentError(
f"Generic alias {argument} requires an argument"
)
elif hasattr(argument, "__forward_arg__"):
argument = argument.__forward_arg__
argument = resolve_name_to_real_class_name(
argument, originating_module
)
if (
self.collection_class is None
and not is_write_only
and not is_dynamic
):
self.uselist = False
# ticket #8759
# if a lead argument was given to relationship(), like
# `relationship("B")`, use that, don't replace it with class we
# found in the annotation. The declarative_scan() method call here is
# still useful, as we continue to derive collection type and do
# checking of the annotation in any case.
if self.argument is None:
self.argument = cast("_RelationshipArgumentType[_T]", argument)
@util.preload_module("sqlalchemy.orm.mapper")
def _setup_entity(self, __argument: Any = None) -> None:
if "entity" in self.__dict__:
return
mapperlib = util.preloaded.orm_mapper
if __argument:
argument = __argument
else:
argument = self.argument
resolved_argument: _ExternalEntityType[Any]
if isinstance(argument, str):
# we might want to cleanup clsregistry API to make this
# more straightforward
resolved_argument = cast(
"_ExternalEntityType[Any]",
self._clsregistry_resolve_name(argument)(),
)
elif callable(argument) and not isinstance(
argument, (type, mapperlib.Mapper)
):
resolved_argument = argument()
else:
resolved_argument = argument
entity: _InternalEntityType[Any]
if isinstance(resolved_argument, type):
entity = class_mapper(resolved_argument, configure=False)
else:
try:
entity = inspect(resolved_argument)
except sa_exc.NoInspectionAvailable:
entity = None # type: ignore
if not hasattr(entity, "mapper"):
raise sa_exc.ArgumentError(
"relationship '%s' expects "
"a class or a mapper argument (received: %s)"
% (self.key, type(resolved_argument))
)
self.entity = entity
self.target = self.entity.persist_selectable
def _setup_join_conditions(self) -> None:
self._join_condition = jc = JoinCondition(
parent_persist_selectable=self.parent.persist_selectable,
child_persist_selectable=self.entity.persist_selectable,
parent_local_selectable=self.parent.local_table,
child_local_selectable=self.entity.local_table,
primaryjoin=self._init_args.primaryjoin.resolved,
secondary=self._init_args.secondary.resolved,
secondaryjoin=self._init_args.secondaryjoin.resolved,
parent_equivalents=self.parent._equivalent_columns,
child_equivalents=self.mapper._equivalent_columns,
consider_as_foreign_keys=self._user_defined_foreign_keys,
local_remote_pairs=self.local_remote_pairs,
remote_side=self.remote_side,
self_referential=self._is_self_referential,
prop=self,
support_sync=not self.viewonly,
can_be_synced_fn=self._columns_are_mapped,
)
self.primaryjoin = jc.primaryjoin
self.secondaryjoin = jc.secondaryjoin
self.secondary = jc.secondary
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
@property
def _clsregistry_resolve_arg(
self,
) -> Callable[[str, bool], _class_resolver]:
return self._clsregistry_resolvers[1]
@property
def _clsregistry_resolve_name(
self,
) -> Callable[[str], Callable[[], Union[Type[Any], Table, _ModNS]]]:
return self._clsregistry_resolvers[0]
@util.memoized_property
@util.preload_module("sqlalchemy.orm.clsregistry")
def _clsregistry_resolvers(
self,
) -> Tuple[
Callable[[str], Callable[[], Union[Type[Any], Table, _ModNS]]],
Callable[[str, bool], _class_resolver],
]:
_resolver = util.preloaded.orm_clsregistry._resolver
return _resolver(self.parent.class_, self)
def _check_conflicts(self) -> None:
"""Test that this relationship is legal, warn about
inheritance conflicts."""
if self.parent.non_primary and not 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__,
)
)
@property
def cascade(self) -> CascadeOptions:
"""Return the current cascade setting for this
:class:`.RelationshipProperty`.
"""
return self._cascade
@cascade.setter
def cascade(self, cascade: Union[str, CascadeOptions]) -> None:
self._set_cascade(cascade)
def _set_cascade(self, cascade_arg: Union[str, CascadeOptions]) -> None:
cascade = CascadeOptions(cascade_arg)
if self.viewonly:
cascade = CascadeOptions(
cascade.intersection(CascadeOptions._viewonly_cascades)
)
if "mapper" in self.__dict__:
self._check_cascade_settings(cascade)
self._cascade = cascade
if self._dependency_processor:
self._dependency_processor.cascade = cascade
def _check_cascade_settings(self, cascade: CascadeOptions) -> None:
if (
cascade.delete_orphan
and not self.single_parent
and (self.direction is MANYTOMANY or self.direction is MANYTOONE)
):
raise sa_exc.ArgumentError(
"For %(direction)s relationship %(rel)s, delete-orphan "
"cascade is normally "
'configured only on the "one" side of a one-to-many '
"relationship, "
'and not on the "many" side of a many-to-one or many-to-many '
"relationship. "
"To force this relationship to allow a particular "
'"%(relatedcls)s" object to be referenced by only '
'a single "%(clsname)s" object at a time via the '
"%(rel)s relationship, which "
"would allow "
"delete-orphan cascade to take place in this direction, set "
"the single_parent=True flag."
% {
"rel": self,
"direction": (
"many-to-one"
if self.direction is MANYTOONE
else "many-to-many"
),
"clsname": self.parent.class_.__name__,
"relatedcls": self.mapper.class_.__name__,
},
code="bbf0",
)
if self.passive_deletes == "all" and (
"delete" in cascade or "delete-orphan" in cascade
):
raise sa_exc.ArgumentError(
"On %s, can't set passive_deletes='all' in conjunction "
"with 'delete' or 'delete-orphan' cascade" % self
)
if cascade.delete_orphan:
self.mapper.primary_mapper()._delete_orphans.append(
(self.key, self.parent.class_)
)
def _persists_for(self, mapper: Mapper[Any]) -> bool:
"""Return True if this property will persist values on behalf
of the given mapper.
"""
return (
self.key in mapper.relationships
and mapper.relationships[self.key] is self
)
def _columns_are_mapped(self, *cols: ColumnElement[Any]) -> bool:
"""Return True if all columns in the given collection are
mapped by the tables referenced by this :class:`.RelationshipProperty`.
"""
secondary = self._init_args.secondary.resolved
for c in cols:
if secondary is not None and secondary.c.contains_column(c):
continue
if not self.parent.persist_selectable.c.contains_column(
c
) and not self.target.c.contains_column(c):
return False
return True
def _generate_backref(self) -> None:
"""Interpret the 'backref' instruction to create a
:func:`_orm.relationship` complementary to this one."""
if self.parent.non_primary:
return
if self.backref is not None and not self.back_populates:
kwargs: Dict[str, Any]
if isinstance(self.backref, str):
backref_key, kwargs = self.backref, {}
else:
backref_key, kwargs = self.backref
mapper = self.mapper.primary_mapper()
if not mapper.concrete:
check = set(mapper.iterate_to_root()).union(
mapper.self_and_descendants
)
for m in check:
if m.has_property(backref_key) and not m.concrete:
raise sa_exc.ArgumentError(
"Error creating backref "
"'%s' on relationship '%s': property of that "
"name exists on mapper '%s'"
% (backref_key, self, m)
)
# determine primaryjoin/secondaryjoin for the
# backref. Use the one we had, so that
# a custom join doesn't have to be specified in
# both directions.
if self.secondary is not None:
# for many to many, just switch primaryjoin/
# secondaryjoin. use the annotated
# pj/sj on the _join_condition.
pj = kwargs.pop(
"primaryjoin",
self._join_condition.secondaryjoin_minus_local,
)
sj = kwargs.pop(
"secondaryjoin",
self._join_condition.primaryjoin_minus_local,
)
else:
pj = kwargs.pop(
"primaryjoin",
self._join_condition.primaryjoin_reverse_remote,
)
sj = kwargs.pop("secondaryjoin", None)
if sj:
raise sa_exc.InvalidRequestError(
"Can't assign 'secondaryjoin' on a backref "
"against a non-secondary relationship."
)
foreign_keys = kwargs.pop(
"foreign_keys", self._user_defined_foreign_keys
)
parent = self.parent.primary_mapper()
kwargs.setdefault("viewonly", self.viewonly)
kwargs.setdefault("post_update", self.post_update)
kwargs.setdefault("passive_updates", self.passive_updates)
kwargs.setdefault("sync_backref", self.sync_backref)
self.back_populates = backref_key
relationship = RelationshipProperty(
parent,
self.secondary,
primaryjoin=pj,
secondaryjoin=sj,
foreign_keys=foreign_keys,
back_populates=self.key,
**kwargs,
)
mapper._configure_property(
backref_key, relationship, warn_for_existing=True
)
if self.back_populates:
self._add_reverse_property(self.back_populates)
@util.preload_module("sqlalchemy.orm.dependency")
def _post_init(self) -> None:
dependency = util.preloaded.orm_dependency
if self.uselist is None:
self.uselist = self.direction is not MANYTOONE
if not self.viewonly:
self._dependency_processor = ( # type: ignore
dependency.DependencyProcessor.from_relationship
)(self)
@util.memoized_property
def _use_get(self) -> bool:
"""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) -> bool:
return self.mapper.common_parent(self.parent)
def _create_joins(
self,
source_polymorphic: bool = False,
source_selectable: Optional[FromClause] = None,
dest_selectable: Optional[FromClause] = None,
of_type_entity: Optional[_InternalEntityType[Any]] = None,
alias_secondary: bool = False,
extra_criteria: Tuple[ColumnElement[bool], ...] = (),
) -> Tuple[
ColumnElement[bool],
Optional[ColumnElement[bool]],
FromClause,
FromClause,
Optional[FromClause],
Optional[ClauseAdapter],
]:
aliased = False
if alias_secondary and self.secondary is not None:
aliased = True
if source_selectable is None:
if source_polymorphic and self.parent.with_polymorphic:
source_selectable = self.parent._with_polymorphic_selectable
if of_type_entity:
dest_mapper = of_type_entity.mapper
if dest_selectable is None:
dest_selectable = of_type_entity.selectable
aliased = True
else:
dest_mapper = self.mapper
if dest_selectable is None:
dest_selectable = self.entity.selectable
if self.mapper.with_polymorphic:
aliased = True
if self._is_self_referential and source_selectable is None:
dest_selectable = dest_selectable._anonymous_fromclause()
aliased = True
elif (
dest_selectable is not self.mapper._with_polymorphic_selectable
or self.mapper.with_polymorphic
):
aliased = True
single_crit = dest_mapper._single_table_criterion
aliased = aliased or (
source_selectable is not None
and (
source_selectable
is not self.parent._with_polymorphic_selectable
or source_selectable._is_subquery
)
)
(
primaryjoin,
secondaryjoin,
secondary,
target_adapter,
dest_selectable,
) = self._join_condition.join_targets(
source_selectable,
dest_selectable,
aliased,
single_crit,
extra_criteria,
)
if source_selectable is None:
source_selectable = self.parent.local_table
if dest_selectable is None:
dest_selectable = self.entity.local_table
return (
primaryjoin,
secondaryjoin,
source_selectable,
dest_selectable,
secondary,
target_adapter,
)
def _annotate_columns(element: _CE, annotations: _AnnotationDict) -> _CE:
def clone(elem: _CE) -> _CE:
if isinstance(elem, expression.ColumnClause):
elem = elem._annotate(annotations.copy()) # type: ignore
elem._copy_internals(clone=clone)
return elem
if element is not None:
element = clone(element)
clone = None # type: ignore # remove gc cycles
return element
class JoinCondition:
primaryjoin_initial: Optional[ColumnElement[bool]]
primaryjoin: ColumnElement[bool]
secondaryjoin: Optional[ColumnElement[bool]]
secondary: Optional[FromClause]
prop: RelationshipProperty[Any]
synchronize_pairs: _ColumnPairs
secondary_synchronize_pairs: _ColumnPairs
direction: RelationshipDirection
parent_persist_selectable: FromClause
child_persist_selectable: FromClause
parent_local_selectable: FromClause
child_local_selectable: FromClause
_local_remote_pairs: Optional[_ColumnPairs]
def __init__(
self,
parent_persist_selectable: FromClause,
child_persist_selectable: FromClause,
parent_local_selectable: FromClause,
child_local_selectable: FromClause,
*,
primaryjoin: Optional[ColumnElement[bool]] = None,
secondary: Optional[FromClause] = None,
secondaryjoin: Optional[ColumnElement[bool]] = None,
parent_equivalents: Optional[_EquivalentColumnMap] = None,
child_equivalents: Optional[_EquivalentColumnMap] = None,
consider_as_foreign_keys: Any = None,
local_remote_pairs: Optional[_ColumnPairs] = None,
remote_side: Any = None,
self_referential: Any = False,
prop: RelationshipProperty[Any],
support_sync: bool = True,
can_be_synced_fn: Callable[..., bool] = lambda *c: True,
):
self.parent_persist_selectable = parent_persist_selectable
self.parent_local_selectable = parent_local_selectable
self.child_persist_selectable = child_persist_selectable
self.child_local_selectable = child_local_selectable
self.parent_equivalents = parent_equivalents
self.child_equivalents = child_equivalents
self.primaryjoin_initial = 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()
assert self.primaryjoin is not None
self._sanitize_joins()
self._annotate_fks()
self._annotate_remote()
self._annotate_local()
self._annotate_parentmapper()
self._setup_pairs()
self._check_foreign_cols(self.primaryjoin, True)
if self.secondaryjoin is not None:
self._check_foreign_cols(self.secondaryjoin, False)
self._determine_direction()
self._check_remote_side()
self._log_joins()
def _log_joins(self) -> None:
log = self.prop.logger
log.info("%s setup primary join %s", self.prop, self.primaryjoin)
log.info("%s setup secondary join %s", self.prop, self.secondaryjoin)
log.info(
"%s synchronize pairs [%s]",
self.prop,
",".join(
"(%s => %s)" % (l, r) for (l, r) in self.synchronize_pairs
),
)
log.info(
"%s secondary synchronize pairs [%s]",
self.prop,
",".join(
"(%s => %s)" % (l, r)
for (l, r) in self.secondary_synchronize_pairs or []
),
)
log.info(
"%s local/remote pairs [%s]",
self.prop,
",".join(
"(%s / %s)" % (l, r) for (l, r) in self.local_remote_pairs
),
)
log.info(
"%s remote columns [%s]",
self.prop,
",".join("%s" % col for col in self.remote_columns),
)
log.info(
"%s local columns [%s]",
self.prop,
",".join("%s" % col for col in self.local_columns),
)
log.info("%s relationship direction %s", self.prop, self.direction)
def _sanitize_joins(self) -> None:
"""remove the parententity annotation from our join conditions which
can leak in here based on some declarative patterns and maybe others.
"parentmapper" is relied upon both by the ORM evaluator as well as
the use case in _join_fixture_inh_selfref_w_entity
that relies upon it being present, see :ticket:`3364`.
"""
self.primaryjoin = _deep_deannotate(
self.primaryjoin, values=("parententity", "proxy_key")
)
if self.secondaryjoin is not None:
self.secondaryjoin = _deep_deannotate(
self.secondaryjoin, values=("parententity", "proxy_key")
)
def _determine_joins(self) -> None:
"""Determine the 'primaryjoin' and 'secondaryjoin' attributes,
if not passed to the constructor already.
This is based on analysis of the foreign key relationships
between the parent and target mapped selectables.
"""
if self.secondaryjoin is not None and self.secondary is None:
raise sa_exc.ArgumentError(
"Property %s specified with secondary "
"join condition but "
"no secondary argument" % self.prop
)
# find a join between the given mapper's mapped table and
# the given table. will try the mapper's local table first
# for more specificity, then if not found will try the more
# general mapped table, which in the case of inheritance is
# a join.
try:
consider_as_foreign_keys = self.consider_as_foreign_keys or None
if self.secondary is not None:
if self.secondaryjoin is None:
self.secondaryjoin = join_condition(
self.child_persist_selectable,
self.secondary,
a_subset=self.child_local_selectable,
consider_as_foreign_keys=consider_as_foreign_keys,
)
if self.primaryjoin_initial is None:
self.primaryjoin = join_condition(
self.parent_persist_selectable,
self.secondary,
a_subset=self.parent_local_selectable,
consider_as_foreign_keys=consider_as_foreign_keys,
)
else:
self.primaryjoin = self.primaryjoin_initial
else:
if self.primaryjoin_initial is None:
self.primaryjoin = join_condition(
self.parent_persist_selectable,
self.child_persist_selectable,
a_subset=self.parent_local_selectable,
consider_as_foreign_keys=consider_as_foreign_keys,
)
else:
self.primaryjoin = self.primaryjoin_initial
except sa_exc.NoForeignKeysError as nfe:
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)
) from nfe
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
) from nfe
except sa_exc.AmbiguousForeignKeysError as afe:
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)
) from afe
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
) from afe
@property
def primaryjoin_minus_local(self) -> ColumnElement[bool]:
return _deep_deannotate(self.primaryjoin, values=("local", "remote"))
@property
def secondaryjoin_minus_local(self) -> ColumnElement[bool]:
assert self.secondaryjoin is not None
return _deep_deannotate(self.secondaryjoin, values=("local", "remote"))
@util.memoized_property
def primaryjoin_reverse_remote(self) -> ColumnElement[bool]:
"""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: _CE, **kw: Any) -> Optional[_CE]:
if "remote" in element._annotations:
v = dict(element._annotations)
del v["remote"]
v["local"] = True
return element._with_annotations(v)
elif "local" in element._annotations:
v = dict(element._annotations)
del v["local"]
v["remote"] = True
return element._with_annotations(v)
return None
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: ClauseElement, annotation: str) -> bool:
for col in visitors.iterate(clause, {}):
if annotation in col._annotations:
return True
else:
return False
@util.memoized_property
def _has_foreign_annotations(self) -> bool:
return self._has_annotation(self.primaryjoin, "foreign")
@util.memoized_property
def _has_remote_annotations(self) -> bool:
return self._has_annotation(self.primaryjoin, "remote")
def _annotate_fks(self) -> None:
"""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) -> None:
def check_fk(element: _CE, **kw: Any) -> Optional[_CE]:
if element in self.consider_as_foreign_keys:
return element._annotate({"foreign": True})
return None
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) -> None:
if self.secondary is not None:
secondarycols = util.column_set(self.secondary.c)
else:
secondarycols = set()
def is_foreign(
a: ColumnElement[Any], b: ColumnElement[Any]
) -> Optional[ColumnElement[Any]]:
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
return None
def visit_binary(binary: BinaryExpression[Any]) -> None:
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) -> bool:
"""Return True if the join condition contains column
comparisons where both columns are in both tables.
"""
pt = self.parent_persist_selectable
mt = self.child_persist_selectable
result = False
def visit_binary(binary: BinaryExpression[Any]) -> None:
nonlocal result
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 = True
visitors.traverse(self.primaryjoin, {}, {"binary": visit_binary})
return result
def _tables_overlap(self) -> bool:
"""Return True if parent/child tables have some overlap."""
return selectables_overlap(
self.parent_persist_selectable, self.child_persist_selectable
)
def _annotate_remote(self) -> None:
"""Annotate the primaryjoin and secondaryjoin
structures with 'remote' annotations marking columns
considered as part of the 'remote' side.
"""
if self._has_remote_annotations:
return
if self.secondary is not None:
self._annotate_remote_secondary()
elif self._local_remote_pairs or self._remote_side:
self._annotate_remote_from_args()
elif self._refers_to_parent_table():
self._annotate_selfref(
lambda col: "foreign" in col._annotations, False
)
elif self._tables_overlap():
self._annotate_remote_with_overlap()
else:
self._annotate_remote_distinct_selectables()
def _annotate_remote_secondary(self) -> None:
"""annotate 'remote' in primaryjoin, secondaryjoin
when 'secondary' is present.
"""
assert self.secondary is not None
fixed_secondary = self.secondary
def repl(element: _CE, **kw: Any) -> Optional[_CE]:
if fixed_secondary.c.contains_column(element):
return element._annotate({"remote": True})
return None
self.primaryjoin = visitors.replacement_traverse(
self.primaryjoin, {}, repl
)
assert self.secondaryjoin is not None
self.secondaryjoin = visitors.replacement_traverse(
self.secondaryjoin, {}, repl
)
def _annotate_selfref(
self, fn: Callable[[ColumnElement[Any]], bool], remote_side_given: bool
) -> None:
"""annotate 'remote' in primaryjoin, secondaryjoin
when the relationship is detected as self-referential.
"""
def visit_binary(binary: BinaryExpression[Any]) -> None:
equated = binary.left.compare(binary.right)
if isinstance(binary.left, expression.ColumnClause) and isinstance(
binary.right, expression.ColumnClause
):
# assume one to many - FKs are "remote"
if fn(binary.left):
binary.left = binary.left._annotate({"remote": True})
if fn(binary.right) and not equated:
binary.right = binary.right._annotate({"remote": True})
elif not remote_side_given:
self._warn_non_column_elements()
self.primaryjoin = visitors.cloned_traverse(
self.primaryjoin, {}, {"binary": visit_binary}
)
def _annotate_remote_from_args(self) -> None:
"""annotate 'remote' in primaryjoin, secondaryjoin
when the 'remote_side' or '_local_remote_pairs'
arguments are used.
"""
if self._local_remote_pairs:
if self._remote_side:
raise sa_exc.ArgumentError(
"remote_side argument is redundant "
"against more detailed _local_remote_side "
"argument."
)
remote_side = [r for (l, r) in self._local_remote_pairs]
else:
remote_side = self._remote_side
if self._refers_to_parent_table():
self._annotate_selfref(lambda col: col in remote_side, True)
else:
def repl(element: _CE, **kw: Any) -> Optional[_CE]:
# use set() to avoid generating ``__eq__()`` expressions
# against each element
if element in set(remote_side):
return element._annotate({"remote": True})
return None
self.primaryjoin = visitors.replacement_traverse(
self.primaryjoin, {}, repl
)
def _annotate_remote_with_overlap(self) -> None:
"""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: BinaryExpression[Any]) -> None:
binary.left, binary.right = proc_left_right(
binary.left, binary.right
)
binary.right, binary.left = proc_left_right(
binary.right, binary.left
)
check_entities = (
self.prop is not None and self.prop.mapper is not self.prop.parent
)
def proc_left_right(
left: ColumnElement[Any], right: ColumnElement[Any]
) -> Tuple[ColumnElement[Any], ColumnElement[Any]]:
if isinstance(left, expression.ColumnClause) and isinstance(
right, expression.ColumnClause
):
if self.child_persist_selectable.c.contains_column(
right
) and self.parent_persist_selectable.c.contains_column(left):
right = right._annotate({"remote": True})
elif (
check_entities
and right._annotations.get("parentmapper") is self.prop.mapper
):
right = right._annotate({"remote": True})
elif (
check_entities
and left._annotations.get("parentmapper") is self.prop.mapper
):
left = left._annotate({"remote": True})
else:
self._warn_non_column_elements()
return left, right
self.primaryjoin = visitors.cloned_traverse(
self.primaryjoin, {}, {"binary": visit_binary}
)
def _annotate_remote_distinct_selectables(self) -> None:
"""annotate 'remote' in primaryjoin, secondaryjoin
when the parent/child tables are entirely
separate.
"""
def repl(element: _CE, **kw: Any) -> Optional[_CE]:
if self.child_persist_selectable.c.contains_column(element) and (
not self.parent_local_selectable.c.contains_column(element)
or self.child_local_selectable.c.contains_column(element)
):
return element._annotate({"remote": True})
return None
self.primaryjoin = visitors.replacement_traverse(
self.primaryjoin, {}, repl
)
def _warn_non_column_elements(self) -> None:
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) -> None:
"""Annotate the primaryjoin and secondaryjoin
structures with 'local' annotations.
This annotates all column elements found
simultaneously in the parent table
and the join condition that don't have a
'remote' annotation set up from
_annotate_remote() or user-defined.
"""
if self._has_annotation(self.primaryjoin, "local"):
return
if self._local_remote_pairs:
local_side = util.column_set(
[l for (l, r) in self._local_remote_pairs]
)
else:
local_side = util.column_set(self.parent_persist_selectable.c)
def locals_(element: _CE, **kw: Any) -> Optional[_CE]:
if "remote" not in element._annotations and element in local_side:
return element._annotate({"local": True})
return None
self.primaryjoin = visitors.replacement_traverse(
self.primaryjoin, {}, locals_
)
def _annotate_parentmapper(self) -> None:
def parentmappers_(element: _CE, **kw: Any) -> Optional[_CE]:
if "remote" in element._annotations:
return element._annotate({"parentmapper": self.prop.mapper})
elif "local" in element._annotations:
return element._annotate({"parentmapper": self.prop.parent})
return None
self.primaryjoin = visitors.replacement_traverse(
self.primaryjoin, {}, parentmappers_
)
def _check_remote_side(self) -> None:
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,)
)
else:
not_target = util.column_set(
self.parent_persist_selectable.c
).difference(self.child_persist_selectable.c)
for _, rmt in self.local_remote_pairs:
if rmt in not_target:
util.warn(
"Expression %s is marked as 'remote', but these "
"column(s) are local to the local side. The "
"remote() annotation is needed only for a "
"self-referential relationship where both sides "
"of the relationship refer to the same tables."
% (rmt,)
)
def _check_foreign_cols(
self, join_condition: ColumnElement[bool], primary: bool
) -> None:
"""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) -> None:
"""Determine if this relationship is one to many, many to one,
many to many.
"""
if self.secondaryjoin is not None:
self.direction = MANYTOMANY
else:
parentcols = util.column_set(self.parent_persist_selectable.c)
targetcols = util.column_set(self.child_persist_selectable.c)
# fk collection which suggests ONETOMANY.
onetomany_fk = targetcols.intersection(self.foreign_key_columns)
# fk collection which suggests MANYTOONE.
manytoone_fk = parentcols.intersection(self.foreign_key_columns)
if onetomany_fk and manytoone_fk:
# fks on both sides. test for overlap of local/remote
# with foreign key.
# we will gather columns directly from their annotations
# without deannotating, so that we can distinguish on a column
# that refers to itself.
# 1. columns that are both remote and FK suggest
# onetomany.
onetomany_local = self._gather_columns_with_annotation(
self.primaryjoin, "remote", "foreign"
)
# 2. columns that are FK but are not remote (e.g. local)
# suggest manytoone.
manytoone_local = {
c
for c in self._gather_columns_with_annotation(
self.primaryjoin, "foreign"
)
if "remote" not in c._annotations
}
# 3. if both collections are present, remove columns that
# refer to themselves. This is for the case of
# and_(Me.id == Me.remote_id, Me.version == Me.version)
if onetomany_local and manytoone_local:
self_equated = self.remote_columns.intersection(
self.local_columns
)
onetomany_local = onetomany_local.difference(self_equated)
manytoone_local = manytoone_local.difference(self_equated)
# at this point, if only one or the other collection is
# present, we know the direction, otherwise it's still
# ambiguous.
if onetomany_local and not manytoone_local:
self.direction = ONETOMANY
elif manytoone_local and not onetomany_local:
self.direction = MANYTOONE
else:
raise sa_exc.ArgumentError(
"Can't determine relationship"
" direction for relationship '%s' - foreign "
"key columns within the join condition are present "
"in both the parent and the child's mapped tables. "
"Ensure that only those columns referring "
"to a parent column are marked as foreign, "
"either via the foreign() annotation or "
"via the foreign_keys argument." % self.prop
)
elif onetomany_fk:
self.direction = ONETOMANY
elif manytoone_fk:
self.direction = MANYTOONE
else:
raise sa_exc.ArgumentError(
"Can't determine relationship "
"direction for relationship '%s' - foreign "
"key columns are present in neither the parent "
"nor the child's mapped tables" % self.prop
)
def _deannotate_pairs(
self, collection: _ColumnPairIterable
) -> _MutableColumnPairs:
"""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) -> None:
sync_pairs: _MutableColumnPairs = []
lrp: util.OrderedSet[Tuple[ColumnElement[Any], ColumnElement[Any]]] = (
util.OrderedSet([])
)
secondary_sync_pairs: _MutableColumnPairs = []
def go(
joincond: ColumnElement[bool],
collection: _MutableColumnPairs,
) -> None:
def visit_binary(
binary: BinaryExpression[Any],
left: ColumnElement[Any],
right: ColumnElement[Any],
) -> None:
if (
"remote" in right._annotations
and "remote" not in left._annotations
and self.can_be_synced_fn(left)
):
lrp.add((left, right))
elif (
"remote" in left._annotations
and "remote" not in right._annotations
and self.can_be_synced_fn(right)
):
lrp.add((right, left))
if binary.operator is operators.eq and self.can_be_synced_fn(
left, right
):
if "foreign" in right._annotations:
collection.append((left, right))
elif "foreign" in left._annotations:
collection.append((right, left))
visit_binary_product(visit_binary, joincond)
for joincond, collection in [
(self.primaryjoin, sync_pairs),
(self.secondaryjoin, secondary_sync_pairs),
]:
if joincond is None:
continue
go(joincond, collection)
self.local_remote_pairs = self._deannotate_pairs(lrp)
self.synchronize_pairs = self._deannotate_pairs(sync_pairs)
self.secondary_synchronize_pairs = self._deannotate_pairs(
secondary_sync_pairs
)
_track_overlapping_sync_targets: weakref.WeakKeyDictionary[
ColumnElement[Any],
weakref.WeakKeyDictionary[
RelationshipProperty[Any], ColumnElement[Any]
],
] = weakref.WeakKeyDictionary()
def _warn_for_conflicting_sync_targets(self) -> None:
if not self.support_sync:
return
# we would like to detect if we are synchronizing any column
# pairs in conflict with another relationship that wishes to sync
# an entirely different column to the same target. This is a
# very rare edge case so we will try to minimize the memory/overhead
# impact of this check
for from_, to_ in [
(from_, to_) for (from_, to_) in self.synchronize_pairs
] + [
(from_, to_) for (from_, to_) in self.secondary_synchronize_pairs
]:
# save ourselves a ton of memory and overhead by only
# considering columns that are subject to a overlapping
# FK constraints at the core level. This condition can arise
# if multiple relationships overlap foreign() directly, but
# we're going to assume it's typically a ForeignKeyConstraint-
# level configuration that benefits from this warning.
if to_ not in self._track_overlapping_sync_targets:
self._track_overlapping_sync_targets[to_] = (
weakref.WeakKeyDictionary({self.prop: from_})
)
else:
other_props = []
prop_to_from = self._track_overlapping_sync_targets[to_]
for pr, fr_ in prop_to_from.items():
if (
not pr.mapper._dispose_called
and pr not in self.prop._reverse_property
and pr.key not in self.prop._overlaps
and self.prop.key not in pr._overlaps
# note: the "__*" symbol is used internally by
# SQLAlchemy as a general means of suppressing the
# overlaps warning for some extension cases, however
# this is not currently
# a publicly supported symbol and may change at
# any time.
and "__*" not in self.prop._overlaps
and "__*" not in pr._overlaps
and not self.prop.parent.is_sibling(pr.parent)
and not self.prop.mapper.is_sibling(pr.mapper)
and not self.prop.parent.is_sibling(pr.mapper)
and not self.prop.mapper.is_sibling(pr.parent)
and (
self.prop.key != pr.key
or not self.prop.parent.common_parent(pr.parent)
)
):
other_props.append((pr, fr_))
if other_props:
util.warn(
"relationship '%s' will copy column %s to column %s, "
"which conflicts with relationship(s): %s. "
"If this is not the intention, consider if these "
"relationships should be linked with "
"back_populates, or if viewonly=True should be "
"applied to one or more if they are read-only. "
"For the less common case that foreign key "
"constraints are partially overlapping, the "
"orm.foreign() "
"annotation can be used to isolate the columns that "
"should be written towards. To silence this "
"warning, add the parameter 'overlaps=\"%s\"' to the "
"'%s' relationship."
% (
self.prop,
from_,
to_,
", ".join(
sorted(
"'%s' (copies %s to %s)" % (pr, fr_, to_)
for (pr, fr_) in other_props
)
),
",".join(sorted(pr.key for pr, fr in other_props)),
self.prop,
),
code="qzyx",
)
self._track_overlapping_sync_targets[to_][self.prop] = from_
@util.memoized_property
def remote_columns(self) -> Set[ColumnElement[Any]]:
return self._gather_join_annotations("remote")
@util.memoized_property
def local_columns(self) -> Set[ColumnElement[Any]]:
return self._gather_join_annotations("local")
@util.memoized_property
def foreign_key_columns(self) -> Set[ColumnElement[Any]]:
return self._gather_join_annotations("foreign")
def _gather_join_annotations(
self, annotation: str
) -> Set[ColumnElement[Any]]:
s = set(
self._gather_columns_with_annotation(self.primaryjoin, annotation)
)
if self.secondaryjoin is not None:
s.update(
self._gather_columns_with_annotation(
self.secondaryjoin, annotation
)
)
return {x._deannotate() for x in s}
def _gather_columns_with_annotation(
self, clause: ColumnElement[Any], *annotation: Iterable[str]
) -> Set[ColumnElement[Any]]:
annotation_set = set(annotation)
return {
cast(ColumnElement[Any], col)
for col in visitors.iterate(clause, {})
if annotation_set.issubset(col._annotations)
}
@util.memoized_property
def _secondary_lineage_set(self) -> FrozenSet[ColumnElement[Any]]:
if self.secondary is not None:
return frozenset(
itertools.chain(*[c.proxy_set for c in self.secondary.c])
)
else:
return util.EMPTY_SET
def join_targets(
self,
source_selectable: Optional[FromClause],
dest_selectable: FromClause,
aliased: bool,
single_crit: Optional[ColumnElement[bool]] = None,
extra_criteria: Tuple[ColumnElement[bool], ...] = (),
) -> Tuple[
ColumnElement[bool],
Optional[ColumnElement[bool]],
Optional[FromClause],
Optional[ClauseAdapter],
FromClause,
]:
"""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 extra_criteria:
def mark_exclude_cols(
elem: SupportsAnnotations, annotations: _AnnotationDict
) -> SupportsAnnotations:
"""note unrelated columns in the "extra criteria" as either
should be adapted or not adapted, even though they are not
part of our "local" or "remote" side.
see #9779 for this case, as well as #11010 for a follow up
"""
parentmapper_for_element = elem._annotations.get(
"parentmapper", None
)
if (
parentmapper_for_element is not self.prop.parent
and parentmapper_for_element is not self.prop.mapper
and elem not in self._secondary_lineage_set
):
return _safe_annotate(elem, annotations)
else:
return elem
extra_criteria = tuple(
_deep_annotate(
elem,
{"should_not_adapt": True},
annotate_callable=mark_exclude_cols,
)
for elem in extra_criteria
)
if secondaryjoin is not None:
secondaryjoin = secondaryjoin & sql.and_(*extra_criteria)
else:
primaryjoin = primaryjoin & sql.and_(*extra_criteria)
if aliased:
if secondary is not None:
secondary = secondary._anonymous_fromclause(flat=True)
primary_aliasizer = ClauseAdapter(
secondary,
exclude_fn=_local_col_exclude,
)
secondary_aliasizer = ClauseAdapter(
dest_selectable, equivalents=self.child_equivalents
).chain(primary_aliasizer)
if source_selectable is not None:
primary_aliasizer = ClauseAdapter(
secondary,
exclude_fn=_local_col_exclude,
).chain(
ClauseAdapter(
source_selectable,
equivalents=self.parent_equivalents,
)
)
secondaryjoin = secondary_aliasizer.traverse(secondaryjoin)
else:
primary_aliasizer = ClauseAdapter(
dest_selectable,
exclude_fn=_local_col_exclude,
equivalents=self.child_equivalents,
)
if source_selectable is not None:
primary_aliasizer.chain(
ClauseAdapter(
source_selectable,
exclude_fn=_remote_col_exclude,
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: bool = False) -> Tuple[
ColumnElement[bool],
Dict[str, ColumnElement[Any]],
Dict[ColumnElement[Any], ColumnElement[Any]],
]:
binds: Dict[ColumnElement[Any], BindParameter[Any]] = {}
equated_columns: Dict[ColumnElement[Any], ColumnElement[Any]] = {}
has_secondary = self.secondaryjoin is not None
if has_secondary:
lookup = collections.defaultdict(list)
for l, r in self.local_remote_pairs:
lookup[l].append((l, r))
equated_columns[r] = l
elif not reverse_direction:
for l, r in self.local_remote_pairs:
equated_columns[r] = l
else:
for l, r in self.local_remote_pairs:
equated_columns[l] = r
def col_to_bind(
element: ColumnElement[Any], **kw: Any
) -> Optional[BindParameter[Any]]:
if (
(not reverse_direction and "local" in element._annotations)
or reverse_direction
and (
(has_secondary and element in lookup)
or (not has_secondary and "remote" in element._annotations)
)
):
if element not in binds:
binds[element] = sql.bindparam(
None, None, type_=element.type, unique=True
)
return binds[element]
return None
lazywhere = self.primaryjoin
if self.secondaryjoin is None or not reverse_direction:
lazywhere = visitors.replacement_traverse(
lazywhere, {}, col_to_bind
)
if self.secondaryjoin is not None:
secondaryjoin = self.secondaryjoin
if reverse_direction:
secondaryjoin = visitors.replacement_traverse(
secondaryjoin, {}, col_to_bind
)
lazywhere = sql.and_(lazywhere, secondaryjoin)
bind_to_col = {binds[col].key: col for col in binds}
return lazywhere, bind_to_col, equated_columns
class _ColInAnnotations:
"""Serializable object that tests for names in c._annotations.
TODO: does this need to be serializable anymore? can we find what the
use case was for that?
"""
__slots__ = ("names",)
def __init__(self, *names: str):
self.names = frozenset(names)
def __call__(self, c: ClauseElement) -> bool:
return bool(self.names.intersection(c._annotations))
_local_col_exclude = _ColInAnnotations("local", "should_not_adapt")
_remote_col_exclude = _ColInAnnotations("remote", "should_not_adapt")
class Relationship(
RelationshipProperty[_T],
_DeclarativeMapped[_T],
):
"""Describes an object property that holds a single item or list
of items that correspond to a related database table.
Public constructor is the :func:`_orm.relationship` function.
.. seealso::
:ref:`relationship_config_toplevel`
.. versionchanged:: 2.0 Added :class:`_orm.Relationship` as a Declarative
compatible subclass for :class:`_orm.RelationshipProperty`.
"""
inherit_cache = True
""":meta private:"""
class _RelationshipDeclared( # type: ignore[misc]
Relationship[_T],
WriteOnlyMapped[_T], # not compatible with Mapped[_T]
DynamicMapped[_T], # not compatible with Mapped[_T]
):
"""Relationship subclass used implicitly for declarative mapping."""
inherit_cache = True
""":meta private:"""
@classmethod
def _mapper_property_name(cls) -> str:
return "Relationship"