From 59141d360e70d1a762719206e3cb0220b4c53fef Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Wed, 14 Aug 2013 19:58:34 -0400 Subject: - apply an import refactoring to the ORM as well - rework the event system so that event modules load after their targets, dependencies are reversed - create an improved strategy lookup system for the ORM - rework the ORM to have very few import cycles - move out "importlater" to just util.dependency - other tricks to cross-populate modules in as clear a way as possible --- lib/sqlalchemy/orm/relationships.py | 1592 ++++++++++++++++++++++++++++++++++- 1 file changed, 1587 insertions(+), 5 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index 33377d3ec..f37bb8a4d 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -13,15 +13,20 @@ and `secondaryjoin` aspects of :func:`.relationship`. """ -from .. import sql, util, exc as sa_exc, schema +from .. import sql, util, exc as sa_exc, schema, log + +from .util import CascadeOptions, _orm_annotate, _orm_deannotate +from . import dependency +from . import attributes from ..sql.util import ( ClauseAdapter, join_condition, _shallow_annotate, visit_binary_product, - _deep_deannotate, find_tables, selectables_overlap + _deep_deannotate, selectables_overlap ) from ..sql import operators, expression, visitors -from .interfaces import MANYTOMANY, MANYTOONE, ONETOMANY - +from .interfaces import MANYTOMANY, MANYTOONE, ONETOMANY, StrategizedProperty, PropComparator +from ..inspection import inspect +from . import mapper as mapperlib def remote(expr): """Annotate a portion of a primaryjoin expression @@ -64,6 +69,1583 @@ def foreign(expr): {"foreign": True}) +@log.class_logger +@util.langhelpers.dependency_for("sqlalchemy.orm.properties") +class RelationshipProperty(StrategizedProperty): + """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. + + See also: + + :ref:`relationship_config_toplevel` + + """ + + strategy_wildcard_key = 'relationship:*' + + _dependency_processor = None + + def __init__(self, argument, + secondary=None, primaryjoin=None, + secondaryjoin=None, + foreign_keys=None, + uselist=None, + order_by=False, + backref=None, + back_populates=None, + post_update=False, + cascade=False, extension=None, + viewonly=False, lazy=True, + collection_class=None, passive_deletes=False, + passive_updates=True, remote_side=None, + enable_typechecks=True, join_depth=None, + comparator_factory=None, + single_parent=False, innerjoin=False, + doc=None, + active_history=False, + cascade_backrefs=True, + load_on_pending=False, + strategy_class=None, _local_remote_pairs=None, + query_class=None, + info=None): + """Provide a relationship of a primary Mapper to a secondary Mapper. + + This corresponds to a parent-child or associative table relationship. The + constructed class is an instance of :class:`.RelationshipProperty`. + + A typical :func:`.relationship`, used in a classical mapping:: + + mapper(Parent, properties={ + 'children': relationship(Child) + }) + + Some arguments accepted by :func:`.relationship` optionally accept a + callable function, which when called produces the desired value. + The callable is invoked by the parent :class:`.Mapper` at "mapper + initialization" time, which happens only when mappers are first used, and + is assumed to be after all mappings have been constructed. This can be + used to resolve order-of-declaration and other dependency issues, such as + if ``Child`` is declared below ``Parent`` in the same file:: + + mapper(Parent, properties={ + "children":relationship(lambda: Child, + order_by=lambda: Child.id) + }) + + When using the :ref:`declarative_toplevel` extension, the Declarative + initializer allows string arguments to be passed to :func:`.relationship`. + These string arguments are converted into callables that evaluate + the string as Python code, using the Declarative + class-registry as a namespace. This allows the lookup of related + classes to be automatic via their string name, and removes the need to + import related classes at all into the local module space:: + + from sqlalchemy.ext.declarative import declarative_base + + Base = declarative_base() + + class Parent(Base): + __tablename__ = 'parent' + id = Column(Integer, primary_key=True) + children = relationship("Child", order_by="Child.id") + + A full array of examples and reference documentation regarding + :func:`.relationship` is at :ref:`relationship_config_toplevel`. + + :param argument: + a mapped class, or actual :class:`.Mapper` instance, representing the + target of the relationship. + + ``argument`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + :param secondary: + for a many-to-many relationship, specifies the intermediary + table, and is an instance of :class:`.Table`. The ``secondary`` keyword + argument should generally only + be used for a table that is not otherwise expressed in any class + mapping, unless this relationship is declared as view only, otherwise + conflicting persistence operations can occur. + + ``secondary`` may + also be passed as a callable function which is evaluated at + mapper initialization time. + + :param active_history=False: + When ``True``, indicates that the "previous" value for a + many-to-one reference should be loaded when replaced, if + not already loaded. Normally, history tracking logic for + simple many-to-ones only needs to be aware of the "new" + value in order to perform a flush. This flag is available + for applications that make use of + :func:`.attributes.get_history` which also need to know + the "previous" value of the attribute. + + :param backref: + indicates the string name of a property to be placed on the related + mapper's class that will handle this relationship in the other + direction. The other property will be created automatically + when the mappers are configured. Can also be passed as a + :func:`backref` object to control the configuration of the + new relationship. + + :param back_populates: + Takes a string name and has the same meaning as ``backref``, + except the complementing property is **not** created automatically, + and instead must be configured explicitly on the other mapper. The + complementing property should also indicate ``back_populates`` + to this relationship to ensure proper functioning. + + :param cascade: + a comma-separated list of cascade rules which determines how + Session operations should be "cascaded" from parent to child. + This defaults to ``False``, which means the default cascade + should be used. The default value is ``"save-update, merge"``. + + Available cascades are: + + * ``save-update`` - cascade the :meth:`.Session.add` + operation. This cascade applies both to future and + past calls to :meth:`~sqlalchemy.orm.session.Session.add`, + meaning new items added to a collection or scalar relationship + get placed into the same session as that of the parent, and + also applies to items which have been removed from this + relationship but are still part of unflushed history. + + * ``merge`` - cascade the :meth:`~sqlalchemy.orm.session.Session.merge` + operation + + * ``expunge`` - cascade the :meth:`.Session.expunge` + operation + + * ``delete`` - cascade the :meth:`.Session.delete` + operation + + * ``delete-orphan`` - if an item of the child's type is + detached from its parent, mark it for deletion. + + .. versionchanged:: 0.7 + This option does not prevent + a new instance of the child object from being persisted + without a parent to start with; to constrain against + that case, ensure the child's foreign key column(s) + is configured as NOT NULL + + * ``refresh-expire`` - cascade the :meth:`.Session.expire` + and :meth:`~sqlalchemy.orm.session.Session.refresh` operations + + * ``all`` - shorthand for "save-update,merge, refresh-expire, + expunge, delete" + + See the section :ref:`unitofwork_cascades` for more background + on configuring cascades. + + :param cascade_backrefs=True: + a boolean value indicating if the ``save-update`` cascade should + operate along an assignment event intercepted by a backref. + When set to ``False``, + the attribute managed by this relationship will not cascade + an incoming transient object into the session of a + persistent parent, if the event is received via backref. + + That is:: + + mapper(A, a_table, properties={ + 'bs':relationship(B, backref="a", cascade_backrefs=False) + }) + + If an ``A()`` is present in the session, assigning it to + the "a" attribute on a transient ``B()`` will not place + the ``B()`` into the session. To set the flag in the other + direction, i.e. so that ``A().bs.append(B())`` won't add + a transient ``A()`` into the session for a persistent ``B()``:: + + mapper(A, a_table, properties={ + 'bs':relationship(B, + backref=backref("a", cascade_backrefs=False) + ) + }) + + See the section :ref:`unitofwork_cascades` for more background + on configuring cascades. + + :param collection_class: + a class or callable that returns a new list-holding object. will + be used in place of a plain list for storing elements. + Behavior of this attribute is described in detail at + :ref:`custom_collections`. + + :param comparator_factory: + a class which extends :class:`.RelationshipProperty.Comparator` which + provides custom SQL clause generation for comparison operations. + + :param doc: + docstring which will be applied to the resulting descriptor. + + :param extension: + an :class:`.AttributeExtension` instance, or list of extensions, + which will be prepended to the list of attribute listeners for + the resulting descriptor placed on the class. + **Deprecated.** Please see :class:`.AttributeEvents`. + + :param foreign_keys: + a list of columns which are to be used as "foreign key" columns, + or columns which refer to the value in a remote column, within the + context of this :func:`.relationship` object's ``primaryjoin`` + condition. That is, if the ``primaryjoin`` condition of this + :func:`.relationship` is ``a.id == b.a_id``, and the values in ``b.a_id`` + are required to be present in ``a.id``, then the "foreign key" column + of this :func:`.relationship` is ``b.a_id``. + + In normal cases, the ``foreign_keys`` parameter is **not required.** + :func:`.relationship` will **automatically** determine which columns + in the ``primaryjoin`` conditition are to be considered "foreign key" + columns based on those :class:`.Column` objects that specify + :class:`.ForeignKey`, or are otherwise listed as referencing columns + in a :class:`.ForeignKeyConstraint` construct. ``foreign_keys`` is only + needed when: + + 1. There is more than one way to construct a join from the local + table to the remote table, as there are multiple foreign key + references present. Setting ``foreign_keys`` will limit the + :func:`.relationship` to consider just those columns specified + here as "foreign". + + .. versionchanged:: 0.8 + A multiple-foreign key join ambiguity can be resolved by + setting the ``foreign_keys`` parameter alone, without the + need to explicitly set ``primaryjoin`` as well. + + 2. The :class:`.Table` being mapped does not actually have + :class:`.ForeignKey` or :class:`.ForeignKeyConstraint` + constructs present, often because the table + was reflected from a database that does not support foreign key + reflection (MySQL MyISAM). + + 3. The ``primaryjoin`` argument is used to construct a non-standard + join condition, which makes use of columns or expressions that do + not normally refer to their "parent" column, such as a join condition + expressed by a complex comparison using a SQL function. + + The :func:`.relationship` construct will raise informative error messages + that suggest the use of the ``foreign_keys`` parameter when presented + with an ambiguous condition. In typical cases, if :func:`.relationship` + doesn't raise any exceptions, the ``foreign_keys`` parameter is usually + not needed. + + ``foreign_keys`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + .. seealso:: + + :ref:`relationship_foreign_keys` + + :ref:`relationship_custom_foreign` + + :func:`.foreign` - allows direct annotation of the "foreign" columns + within a ``primaryjoin`` condition. + + .. versionadded:: 0.8 + The :func:`.foreign` annotation can also be applied + directly to the ``primaryjoin`` expression, which is an alternate, + more specific system of describing which columns in a particular + ``primaryjoin`` should be considered "foreign". + + :param info: Optional data dictionary which will be populated into the + :attr:`.MapperProperty.info` attribute of this object. + + .. versionadded:: 0.8 + + :param innerjoin=False: + when ``True``, joined eager loads will use an inner join to join + against related tables instead of an outer join. The purpose + of this option is generally one of performance, as inner joins + generally perform better than outer joins. Another reason can be + the use of ``with_lockmode``, which does not support outer joins. + + This flag can be set to ``True`` when the relationship references an + object via many-to-one using local foreign keys that are not nullable, + or when the reference is one-to-one or a collection that is guaranteed + to have one or at least one entry. + + :param join_depth: + when non-``None``, an integer value indicating how many levels + deep "eager" loaders should join on a self-referring or cyclical + relationship. The number counts how many times the same Mapper + shall be present in the loading condition along a particular join + branch. When left at its default of ``None``, eager loaders + will stop chaining when they encounter a the same target mapper + which is already higher up in the chain. This option applies + both to joined- and subquery- eager loaders. + + :param lazy='select': specifies + how the related items should be loaded. Default value is + ``select``. Values include: + + * ``select`` - items should be loaded lazily when the property is first + accessed, using a separate SELECT statement, or identity map + fetch for simple many-to-one references. + + * ``immediate`` - items should be loaded as the parents are loaded, + using a separate SELECT statement, or identity map fetch for + simple many-to-one references. + + .. versionadded:: 0.6.5 + + * ``joined`` - items should be loaded "eagerly" in the same query as + that of the parent, using a JOIN or LEFT OUTER JOIN. Whether + the join is "outer" or not is determined by the ``innerjoin`` + parameter. + + * ``subquery`` - items should be loaded "eagerly" as the parents are + loaded, using one additional SQL statement, which issues a JOIN to a + subquery of the original statement, for each collection requested. + + * ``noload`` - no loading should occur at any time. This is to + support "write-only" attributes, or attributes which are + populated in some manner specific to the application. + + * ``dynamic`` - the attribute will return a pre-configured + :class:`~sqlalchemy.orm.query.Query` object for all read + operations, onto which further filtering operations can be + applied before iterating the results. See + the section :ref:`dynamic_relationship` for more details. + + * True - a synonym for 'select' + + * False - a synonym for 'joined' + + * None - a synonym for 'noload' + + Detailed discussion of loader strategies is at :doc:`/orm/loading`. + + :param load_on_pending=False: + Indicates loading behavior for transient or pending parent objects. + + .. versionchanged:: 0.8 + load_on_pending is superseded by + :meth:`.Session.enable_relationship_loading`. + + When set to ``True``, causes the lazy-loader to + issue a query for a parent object that is not persistent, meaning it has + never been flushed. This may take effect for a pending object when + autoflush is disabled, or for a transient object that has been + "attached" to a :class:`.Session` but is not part of its pending + collection. + + The load_on_pending flag does not improve behavior + when the ORM is used normally - object references should be constructed + at the object level, not at the foreign key level, so that they + are present in an ordinary way before flush() proceeds. This flag + is not not intended for general use. + + .. versionadded:: 0.6.5 + + :param order_by: + indicates the ordering that should be applied when loading these + items. ``order_by`` is expected to refer to one of the :class:`.Column` + objects to which the target class is mapped, or + the attribute itself bound to the target class which refers + to the column. + + ``order_by`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + :param passive_deletes=False: + Indicates loading behavior during delete operations. + + A value of True indicates that unloaded child items should not + be loaded during a delete operation on the parent. Normally, + when a parent item is deleted, all child items are loaded so + that they can either be marked as deleted, or have their + foreign key to the parent set to NULL. Marking this flag as + True usually implies an ON DELETE rule is in + place which will handle updating/deleting child rows on the + database side. + + Additionally, setting the flag to the string value 'all' will + disable the "nulling out" of the child foreign keys, when there + is no delete or delete-orphan cascade enabled. This is + typically used when a triggering or error raise scenario is in + place on the database side. Note that the foreign key + attributes on in-session child objects will not be changed + after a flush occurs so this is a very special use-case + setting. + + :param passive_updates=True: + Indicates loading and INSERT/UPDATE/DELETE behavior when the + source of a foreign key value changes (i.e. an "on update" + cascade), which are typically the primary key columns of the + source row. + + When True, it is assumed that ON UPDATE CASCADE is configured on + the foreign key in the database, and that the database will + handle propagation of an UPDATE from a source column to + dependent rows. Note that with databases which enforce + referential integrity (i.e. PostgreSQL, MySQL with InnoDB tables), + ON UPDATE CASCADE is required for this operation. The + relationship() will update the value of the attribute on related + items which are locally present in the session during a flush. + + When False, it is assumed that the database does not enforce + referential integrity and will not be issuing its own CASCADE + operation for an update. The relationship() will issue the + appropriate UPDATE statements to the database in response to the + change of a referenced key, and items locally present in the + session during a flush will also be refreshed. + + This flag should probably be set to False if primary key changes + are expected and the database in use doesn't support CASCADE + (i.e. SQLite, MySQL MyISAM tables). + + Also see the passive_updates flag on ``mapper()``. + + A future SQLAlchemy release will provide a "detect" feature for + this flag. + + :param post_update: + this indicates that the relationship should be handled by a + second UPDATE statement after an INSERT or before a + DELETE. Currently, it also will issue an UPDATE after the + instance was UPDATEd as well, although this technically should + be improved. This flag is used to handle saving bi-directional + dependencies between two individual rows (i.e. each row + references the other), where it would otherwise be impossible to + INSERT or DELETE both rows fully since one row exists before the + other. Use this flag when a particular mapping arrangement will + incur two rows that are dependent on each other, such as a table + that has a one-to-many relationship to a set of child rows, and + also has a column that references a single child row within that + list (i.e. both tables contain a foreign key to each other). If + a ``flush()`` operation returns an error that a "cyclical + dependency" was detected, this is a cue that you might want to + use ``post_update`` to "break" the cycle. + + :param primaryjoin: + a SQL expression that will be used as the primary + join of this child object against the parent object, or in a + many-to-many relationship the join of the primary object to the + association table. By default, this value is computed based on the + foreign key relationships of the parent and child tables (or association + table). + + ``primaryjoin`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + :param remote_side: + used for self-referential relationships, indicates the column or + list of columns that form the "remote side" of the relationship. + + ``remote_side`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + .. versionchanged:: 0.8 + The :func:`.remote` annotation can also be applied + directly to the ``primaryjoin`` expression, which is an alternate, + more specific system of describing which columns in a particular + ``primaryjoin`` should be considered "remote". + + :param query_class: + a :class:`.Query` subclass that will be used as the base of the + "appender query" returned by a "dynamic" relationship, that + is, a relationship that specifies ``lazy="dynamic"`` or was + otherwise constructed using the :func:`.orm.dynamic_loader` + function. + + :param secondaryjoin: + a SQL expression that will be used as the join of + an association table to the child object. By default, this value is + computed based on the foreign key relationships of the association and + child tables. + + ``secondaryjoin`` may also be passed as a callable function + which is evaluated at mapper initialization time, and may be passed as a + Python-evaluable string when using Declarative. + + :param single_parent=(True|False): + when True, installs a validator which will prevent objects + from being associated with more than one parent at a time. + This is used for many-to-one or many-to-many relationships that + should be treated either as one-to-one or one-to-many. Its + usage is optional unless delete-orphan cascade is also + set on this relationship(), in which case its required. + + :param uselist=(True|False): + a boolean that indicates if this property should be loaded as a + list or a scalar. In most cases, this value is determined + automatically by ``relationship()``, based on the type and direction + of the relationship - one to many forms a list, many to one + forms a scalar, many to many is a list. If a scalar is desired + where normally a list would be present, such as a bi-directional + one-to-one relationship, set uselist to False. + + :param viewonly=False: + when set to True, the relationship is used only for loading objects + within the relationship, and has no effect on the unit-of-work + flush process. Relationships with viewonly can specify any kind of + join conditions to provide additional views of related objects + onto a parent object. Note that the functionality of a viewonly + relationship has its limits - complicated join conditions may + not compile into eager or lazy loaders properly. If this is the + case, use an alternative method. + + .. versionchanged:: 0.6 + :func:`relationship` was renamed from its previous name + :func:`relation`. + + """ + + self.uselist = uselist + self.argument = argument + self.secondary = secondary + self.primaryjoin = primaryjoin + self.secondaryjoin = secondaryjoin + self.post_update = post_update + self.direction = None + self.viewonly = viewonly + self.lazy = lazy + self.single_parent = single_parent + self._user_defined_foreign_keys = foreign_keys + self.collection_class = collection_class + self.passive_deletes = passive_deletes + self.cascade_backrefs = cascade_backrefs + self.passive_updates = passive_updates + self.remote_side = remote_side + self.enable_typechecks = enable_typechecks + self.query_class = query_class + self.innerjoin = innerjoin + self.doc = doc + self.active_history = active_history + self.join_depth = join_depth + self.local_remote_pairs = _local_remote_pairs + self.extension = extension + self.load_on_pending = load_on_pending + self.comparator_factory = comparator_factory or \ + RelationshipProperty.Comparator + self.comparator = self.comparator_factory(self, None) + util.set_creation_order(self) + + if info is not None: + self.info = info + + if strategy_class: + self.strategy_class = strategy_class + else: + self.strategy_class = self._strategy_lookup(lazy=self.lazy) + self._lazy_strategy = self._strategy_lookup(lazy="select") + + self._reverse_property = set() + + self.cascade = cascade if cascade is not False \ + else "save-update, merge" + + self.order_by = order_by + + self.back_populates = back_populates + + if self.back_populates: + if backref: + raise sa_exc.ArgumentError( + "backref and back_populates keyword arguments " + "are mutually exclusive") + self.backref = None + else: + self.backref = backref + + def instrument_class(self, mapper): + attributes.register_descriptor( + mapper.class_, + self.key, + comparator=self.comparator_factory(self, mapper), + parententity=mapper, + doc=self.doc, + ) + + class Comparator(PropComparator): + """Produce boolean, comparison, and other operators for + :class:`.RelationshipProperty` attributes. + + See the documentation for :class:`.PropComparator` for a brief overview + of ORM level operator definition. + + See also: + + :class:`.PropComparator` + + :class:`.ColumnProperty.Comparator` + + :class:`.ColumnOperators` + + :ref:`types_operators` + + :attr:`.TypeEngine.comparator_factory` + + """ + + _of_type = None + + def __init__(self, prop, parentmapper, adapt_to_entity=None, of_type=None): + """Construction of :class:`.RelationshipProperty.Comparator` + is internal to the ORM's attribute mechanics. + + """ + self.prop = prop + self._parentmapper = parentmapper + self._adapt_to_entity = adapt_to_entity + if of_type: + self._of_type = of_type + + def adapt_to_entity(self, adapt_to_entity): + return self.__class__(self.property, self._parentmapper, + adapt_to_entity=adapt_to_entity, + of_type=self._of_type) + + @util.memoized_property + def mapper(self): + """The target :class:`.Mapper` referred to by this + :class:`.RelationshipProperty.Comparator. + + This is the "target" or "remote" side of the + :func:`.relationship`. + + """ + return self.property.mapper + + @util.memoized_property + def _parententity(self): + return self.property.parent + + def _source_selectable(self): + elem = self.property.parent._with_polymorphic_selectable + if self.adapter: + return self.adapter(elem) + else: + return elem + + def __clause_element__(self): + adapt_from = self._source_selectable() + if self._of_type: + of_type = inspect(self._of_type).mapper + else: + of_type = None + + pj, sj, source, dest, \ + secondary, target_adapter = self.property._create_joins( + source_selectable=adapt_from, + source_polymorphic=True, + of_type=of_type) + if sj is not None: + return pj & sj + else: + return pj + + def of_type(self, cls): + """Produce a construct that represents a particular 'subtype' of + attribute for the parent class. + + Currently this is usable in conjunction with :meth:`.Query.join` + and :meth:`.Query.outerjoin`. + + """ + return RelationshipProperty.Comparator( + self.property, + self._parentmapper, + adapt_to_entity=self._adapt_to_entity, + of_type=cls) + + def in_(self, other): + """Produce an IN clause - this is not implemented + for :func:`~.orm.relationship`-based attributes at this time. + + """ + raise NotImplementedError('in_() not yet supported for ' + 'relationships. For a simple many-to-one, use ' + 'in_() against the set of foreign key values.') + + __hash__ = None + + def __eq__(self, other): + """Implement the ``==`` operator. + + In a many-to-one context, such as:: + + MyClass.some_prop == + + this will typically produce a + clause such as:: + + mytable.related_id == + + Where ```` is the primary key of the given + object. + + The ``==`` operator provides partial functionality for non- + many-to-one comparisons: + + * Comparisons against collections are not supported. + Use :meth:`~.RelationshipProperty.Comparator.contains`. + * Compared to a scalar one-to-many, will produce a + clause that compares the target columns in the parent to + the given target. + * Compared to a scalar many-to-many, an alias + of the association table will be rendered as + well, forming a natural join that is part of the + main body of the query. This will not work for + queries that go beyond simple AND conjunctions of + comparisons, such as those which use OR. Use + explicit joins, outerjoins, or + :meth:`~.RelationshipProperty.Comparator.has` for + more comprehensive non-many-to-one scalar + membership tests. + * Comparisons against ``None`` given in a one-to-many + or many-to-many context produce a NOT EXISTS clause. + + """ + if isinstance(other, (util.NoneType, expression.Null)): + if self.property.direction in [ONETOMANY, MANYTOMANY]: + return ~self._criterion_exists() + else: + return _orm_annotate(self.property._optimized_compare( + None, adapt_source=self.adapter)) + elif self.property.uselist: + raise sa_exc.InvalidRequestError("Can't compare a colle" + "ction to an object or collection; use " + "contains() to test for membership.") + else: + return _orm_annotate(self.property._optimized_compare(other, + adapt_source=self.adapter)) + + def _criterion_exists(self, criterion=None, **kwargs): + if getattr(self, '_of_type', None): + info = inspect(self._of_type) + target_mapper, to_selectable, is_aliased_class = \ + info.mapper, info.selectable, info.is_aliased_class + if self.property._is_self_referential and not is_aliased_class: + to_selectable = to_selectable.alias() + + single_crit = target_mapper._single_table_criterion + if single_crit is not None: + if criterion is not None: + criterion = single_crit & criterion + else: + criterion = single_crit + else: + is_aliased_class = False + to_selectable = None + + if self.adapter: + source_selectable = self._source_selectable() + else: + source_selectable = None + + pj, sj, source, dest, secondary, target_adapter = \ + self.property._create_joins(dest_polymorphic=True, + dest_selectable=to_selectable, + source_selectable=source_selectable) + + for k in kwargs: + crit = getattr(self.property.mapper.class_, k) == kwargs[k] + if criterion is None: + criterion = crit + else: + criterion = criterion & crit + + # annotate the *local* side of the join condition, in the case + # of pj + sj this is the full primaryjoin, in the case of just + # pj its the local side of the primaryjoin. + if sj is not None: + j = _orm_annotate(pj) & sj + else: + j = _orm_annotate(pj, exclude=self.property.remote_side) + + if criterion is not None and target_adapter and not is_aliased_class: + # limit this adapter to annotated only? + criterion = target_adapter.traverse(criterion) + + # only have the "joined left side" of what we + # return be subject to Query adaption. The right + # side of it is used for an exists() subquery and + # should not correlate or otherwise reach out + # to anything in the enclosing query. + if criterion is not None: + criterion = criterion._annotate( + {'no_replacement_traverse': True}) + + crit = j & criterion + + ex = sql.exists([1], crit, from_obj=dest).correlate_except(dest) + if secondary is not None: + ex = ex.correlate_except(secondary) + return ex + + def any(self, criterion=None, **kwargs): + """Produce an expression that tests a collection against + particular criterion, using EXISTS. + + An expression like:: + + session.query(MyClass).filter( + MyClass.somereference.any(SomeRelated.x==2) + ) + + + Will produce a query like:: + + SELECT * FROM my_table WHERE + EXISTS (SELECT 1 FROM related WHERE related.my_id=my_table.id + AND related.x=2) + + Because :meth:`~.RelationshipProperty.Comparator.any` uses + a correlated subquery, its performance is not nearly as + good when compared against large target tables as that of + using a join. + + :meth:`~.RelationshipProperty.Comparator.any` is particularly + useful for testing for empty collections:: + + session.query(MyClass).filter( + ~MyClass.somereference.any() + ) + + will produce:: + + SELECT * FROM my_table WHERE + NOT EXISTS (SELECT 1 FROM related WHERE + related.my_id=my_table.id) + + :meth:`~.RelationshipProperty.Comparator.any` is only + valid for collections, i.e. a :func:`.relationship` + that has ``uselist=True``. For scalar references, + use :meth:`~.RelationshipProperty.Comparator.has`. + + """ + if not self.property.uselist: + raise sa_exc.InvalidRequestError( + "'any()' not implemented for scalar " + "attributes. Use has()." + ) + + return self._criterion_exists(criterion, **kwargs) + + def has(self, criterion=None, **kwargs): + """Produce an expression that tests a scalar reference against + particular criterion, using EXISTS. + + An expression like:: + + session.query(MyClass).filter( + MyClass.somereference.has(SomeRelated.x==2) + ) + + + Will produce a query like:: + + SELECT * FROM my_table WHERE + EXISTS (SELECT 1 FROM related WHERE + related.id==my_table.related_id AND related.x=2) + + Because :meth:`~.RelationshipProperty.Comparator.has` uses + a correlated subquery, its performance is not nearly as + good when compared against large target tables as that of + using a join. + + :meth:`~.RelationshipProperty.Comparator.has` is only + valid for scalar references, i.e. a :func:`.relationship` + that has ``uselist=False``. For collection references, + use :meth:`~.RelationshipProperty.Comparator.any`. + + """ + if self.property.uselist: + raise sa_exc.InvalidRequestError( + "'has()' not implemented for collections. " + "Use any().") + return self._criterion_exists(criterion, **kwargs) + + def contains(self, other, **kwargs): + """Return a simple expression that tests a collection for + containment of a particular item. + + :meth:`~.RelationshipProperty.Comparator.contains` is + only valid for a collection, i.e. a + :func:`~.orm.relationship` that implements + one-to-many or many-to-many with ``uselist=True``. + + When used in a simple one-to-many context, an + expression like:: + + MyClass.contains(other) + + Produces a clause like:: + + mytable.id == + + Where ```` is the value of the foreign key + attribute on ``other`` which refers to the primary + key of its parent object. From this it follows that + :meth:`~.RelationshipProperty.Comparator.contains` is + very useful when used with simple one-to-many + operations. + + For many-to-many operations, the behavior of + :meth:`~.RelationshipProperty.Comparator.contains` + has more caveats. The association table will be + rendered in the statement, producing an "implicit" + join, that is, includes multiple tables in the FROM + clause which are equated in the WHERE clause:: + + query(MyClass).filter(MyClass.contains(other)) + + Produces a query like:: + + SELECT * FROM my_table, my_association_table AS + my_association_table_1 WHERE + my_table.id = my_association_table_1.parent_id + AND my_association_table_1.child_id = + + Where ```` would be the primary key of + ``other``. From the above, it is clear that + :meth:`~.RelationshipProperty.Comparator.contains` + will **not** work with many-to-many collections when + used in queries that move beyond simple AND + conjunctions, such as multiple + :meth:`~.RelationshipProperty.Comparator.contains` + expressions joined by OR. In such cases subqueries or + explicit "outer joins" will need to be used instead. + See :meth:`~.RelationshipProperty.Comparator.any` for + a less-performant alternative using EXISTS, or refer + to :meth:`.Query.outerjoin` as well as :ref:`ormtutorial_joins` + for more details on constructing outer joins. + + """ + if not self.property.uselist: + raise sa_exc.InvalidRequestError( + "'contains' not implemented for scalar " + "attributes. Use ==") + clause = self.property._optimized_compare(other, + adapt_source=self.adapter) + + if self.property.secondaryjoin is not None: + clause.negation_clause = \ + self.__negated_contains_or_equals(other) + + return clause + + def __negated_contains_or_equals(self, other): + if self.property.direction == MANYTOONE: + state = attributes.instance_state(other) + + def state_bindparam(x, state, col): + o = state.obj() # strong ref + return sql.bindparam(x, unique=True, callable_=lambda: \ + self.property.mapper._get_committed_attr_by_column(o, col)) + + def adapt(col): + if self.adapter: + return self.adapter(col) + else: + return col + + if self.property._use_get: + return sql.and_(*[ + sql.or_( + adapt(x) != state_bindparam(adapt(x), state, y), + adapt(x) == None) + for (x, y) in self.property.local_remote_pairs]) + + criterion = sql.and_(*[x == y for (x, y) in + zip( + self.property.mapper.primary_key, + self.property.\ + mapper.\ + primary_key_from_instance(other)) + ]) + return ~self._criterion_exists(criterion) + + def __ne__(self, other): + """Implement the ``!=`` operator. + + In a many-to-one context, such as:: + + MyClass.some_prop != + + This will typically produce a clause such as:: + + mytable.related_id != + + Where ```` is the primary key of the + given object. + + The ``!=`` operator provides partial functionality for non- + many-to-one comparisons: + + * Comparisons against collections are not supported. + Use + :meth:`~.RelationshipProperty.Comparator.contains` + in conjunction with :func:`~.expression.not_`. + * Compared to a scalar one-to-many, will produce a + clause that compares the target columns in the parent to + the given target. + * Compared to a scalar many-to-many, an alias + of the association table will be rendered as + well, forming a natural join that is part of the + main body of the query. This will not work for + queries that go beyond simple AND conjunctions of + comparisons, such as those which use OR. Use + explicit joins, outerjoins, or + :meth:`~.RelationshipProperty.Comparator.has` in + conjunction with :func:`~.expression.not_` for + more comprehensive non-many-to-one scalar + membership tests. + * Comparisons against ``None`` given in a one-to-many + or many-to-many context produce an EXISTS clause. + + """ + if isinstance(other, (util.NoneType, expression.Null)): + if self.property.direction == MANYTOONE: + return sql.or_(*[x != None for x in + self.property._calculated_foreign_keys]) + else: + return self._criterion_exists() + elif self.property.uselist: + raise sa_exc.InvalidRequestError("Can't compare a collection" + " to an object or collection; use " + "contains() to test for membership.") + else: + return self.__negated_contains_or_equals(other) + + @util.memoized_property + def property(self): + if mapperlib.Mapper._new_mappers: + mapperlib.Mapper._configure_all() + return self.prop + + def compare(self, op, value, + value_is_parent=False, + alias_secondary=True): + if op == operators.eq: + if value is None: + if self.uselist: + return ~sql.exists([1], self.primaryjoin) + else: + return self._optimized_compare(None, + value_is_parent=value_is_parent, + alias_secondary=alias_secondary) + else: + return self._optimized_compare(value, + value_is_parent=value_is_parent, + alias_secondary=alias_secondary) + else: + return op(self.comparator, value) + + def _optimized_compare(self, value, value_is_parent=False, + adapt_source=None, + alias_secondary=True): + if value is not None: + value = attributes.instance_state(value) + return self._get_strategy(self._lazy_strategy).lazy_clause(value, + reverse_direction=not value_is_parent, + alias_secondary=alias_secondary, + adapt_source=adapt_source) + + def __str__(self): + return str(self.parent.class_.__name__) + "." + self.key + + def merge(self, + session, + source_state, + source_dict, + dest_state, + dest_dict, + load, _recursive): + + if load: + for r in self._reverse_property: + if (source_state, r) in _recursive: + return + + if not "merge" in self._cascade: + return + + if self.key not in source_dict: + return + + if self.uselist: + instances = source_state.get_impl(self.key).\ + get(source_state, source_dict) + if hasattr(instances, '_sa_adapter'): + # convert collections to adapters to get a true iterator + instances = instances._sa_adapter + + if load: + # for a full merge, pre-load the destination collection, + # so that individual _merge of each item pulls from identity + # map for those already present. + # also assumes CollectionAttrbiuteImpl behavior of loading + # "old" list in any case + dest_state.get_impl(self.key).get(dest_state, dest_dict) + + dest_list = [] + for current in instances: + current_state = attributes.instance_state(current) + current_dict = attributes.instance_dict(current) + _recursive[(current_state, self)] = True + obj = session._merge(current_state, current_dict, + load=load, _recursive=_recursive) + if obj is not None: + dest_list.append(obj) + + if not load: + coll = attributes.init_state_collection(dest_state, + dest_dict, self.key) + for c in dest_list: + coll.append_without_event(c) + else: + dest_state.get_impl(self.key)._set_iterable(dest_state, + dest_dict, dest_list) + else: + current = source_dict[self.key] + if current is not None: + current_state = attributes.instance_state(current) + current_dict = attributes.instance_dict(current) + _recursive[(current_state, self)] = True + obj = session._merge(current_state, current_dict, + load=load, _recursive=_recursive) + else: + obj = None + + if not load: + dest_dict[self.key] = obj + else: + dest_state.get_impl(self.key).set(dest_state, + dest_dict, obj, None) + + def _value_as_iterable(self, state, dict_, key, + passive=attributes.PASSIVE_OFF): + """Return a list of tuples (state, obj) for the given + key. + + returns an empty list if the value is None/empty/PASSIVE_NO_RESULT + """ + + impl = state.manager[key].impl + x = impl.get(state, dict_, passive=passive) + if x is attributes.PASSIVE_NO_RESULT or x is None: + return [] + elif hasattr(impl, 'get_collection'): + return [ + (attributes.instance_state(o), o) for o in + impl.get_collection(state, dict_, x, passive=passive) + ] + else: + return [(attributes.instance_state(x), x)] + + def cascade_iterator(self, type_, state, dict_, + visited_states, halt_on=None): + #assert type_ in self._cascade + + # only actively lazy load on the 'delete' cascade + if type_ != 'delete' or self.passive_deletes: + passive = attributes.PASSIVE_NO_INITIALIZE + else: + passive = attributes.PASSIVE_OFF + + if type_ == 'save-update': + tuples = state.manager[self.key].impl.\ + get_all_pending(state, dict_) + + else: + tuples = self._value_as_iterable(state, dict_, self.key, + passive=passive) + + skip_pending = type_ == 'refresh-expire' and 'delete-orphan' \ + not in self._cascade + + for instance_state, c in tuples: + if instance_state in visited_states: + continue + + if c is None: + # would like to emit a warning here, but + # would not be consistent with collection.append(None) + # current behavior of silently skipping. + # see [ticket:2229] + continue + + instance_dict = attributes.instance_dict(c) + + if halt_on and halt_on(instance_state): + continue + + if skip_pending and not instance_state.key: + continue + + instance_mapper = instance_state.manager.mapper + + if not instance_mapper.isa(self.mapper.class_manager.mapper): + raise AssertionError("Attribute '%s' on class '%s' " + "doesn't handle objects " + "of type '%s'" % ( + self.key, + self.parent.class_, + c.__class__ + )) + + visited_states.add(instance_state) + + yield c, instance_mapper, instance_state, instance_dict + + def _add_reverse_property(self, key): + other = self.mapper.get_property(key, _configure_mappers=False) + self._reverse_property.add(other) + other._reverse_property.add(self) + + if not other.mapper.common_parent(self.parent): + raise sa_exc.ArgumentError('reverse_property %r on ' + 'relationship %s references relationship %s, which ' + 'does not reference mapper %s' % (key, self, other, + self.parent)) + if self.direction in (ONETOMANY, MANYTOONE) and self.direction \ + == other.direction: + raise sa_exc.ArgumentError('%s and back-reference %s are ' + 'both of the same direction %r. Did you mean to ' + 'set remote_side on the many-to-one side ?' + % (other, self, self.direction)) + + @util.memoized_property + def mapper(self): + """Return the targeted :class:`.Mapper` for this + :class:`.RelationshipProperty`. + + This is a lazy-initializing static attribute. + + """ + if isinstance(self.argument, type): + mapper_ = mapperlib.class_mapper(self.argument, + configure=False) + elif isinstance(self.argument, mapperlib.Mapper): + mapper_ = self.argument + elif util.callable(self.argument): + + # accept a callable to suit various deferred- + # configurational schemes + + mapper_ = mapperlib.class_mapper(self.argument(), + configure=False) + else: + raise sa_exc.ArgumentError("relationship '%s' expects " + "a class or a mapper argument (received: %s)" + % (self.key, type(self.argument))) + assert isinstance(mapper_, mapperlib.Mapper), mapper_ + return mapper_ + + @util.memoized_property + @util.deprecated("0.7", "Use .target") + def table(self): + """Return the selectable linked to this + :class:`.RelationshipProperty` object's target + :class:`.Mapper`.""" + return self.target + + def do_init(self): + self._check_conflicts() + self._process_dependent_arguments() + self._setup_join_conditions() + self._check_cascade_settings(self._cascade) + self._post_init() + self._generate_backref() + super(RelationshipProperty, self).do_init() + + def _process_dependent_arguments(self): + """Convert incoming configuration arguments to their + proper form. + + Callables are resolved, ORM annotations removed. + + """ + # accept callables for other attributes which may require + # deferred initialization. This technique is used + # by declarative "string configs" and some recipes. + for attr in ( + 'order_by', 'primaryjoin', 'secondaryjoin', + 'secondary', '_user_defined_foreign_keys', 'remote_side', + ): + attr_value = getattr(self, attr) + if util.callable(attr_value): + setattr(self, attr, attr_value()) + + # remove "annotations" which are present if mapped class + # descriptors are used to create the join expression. + for attr in 'primaryjoin', 'secondaryjoin': + val = getattr(self, attr) + if val is not None: + setattr(self, attr, _orm_deannotate( + expression._only_column_elements(val, attr)) + ) + + # ensure expressions in self.order_by, foreign_keys, + # remote_side are all columns, not strings. + if self.order_by is not False and self.order_by is not None: + self.order_by = [ + expression._only_column_elements(x, "order_by") + for x in + util.to_list(self.order_by)] + + self._user_defined_foreign_keys = \ + util.column_set( + expression._only_column_elements(x, "foreign_keys") + for x in util.to_column_set( + self._user_defined_foreign_keys + )) + + self.remote_side = \ + util.column_set( + expression._only_column_elements(x, "remote_side") + for x in + util.to_column_set(self.remote_side)) + + self.target = self.mapper.mapped_table + + + def _setup_join_conditions(self): + self._join_condition = jc = JoinCondition( + parent_selectable=self.parent.mapped_table, + child_selectable=self.mapper.mapped_table, + parent_local_selectable=self.parent.local_table, + child_local_selectable=self.mapper.local_table, + primaryjoin=self.primaryjoin, + secondary=self.secondary, + secondaryjoin=self.secondaryjoin, + parent_equivalents=self.parent._equivalent_columns, + child_equivalents=self.mapper._equivalent_columns, + consider_as_foreign_keys=self._user_defined_foreign_keys, + local_remote_pairs=self.local_remote_pairs, + remote_side=self.remote_side, + self_referential=self._is_self_referential, + prop=self, + support_sync=not self.viewonly, + can_be_synced_fn=self._columns_are_mapped + ) + self.primaryjoin = jc.deannotated_primaryjoin + self.secondaryjoin = jc.deannotated_secondaryjoin + self.direction = jc.direction + self.local_remote_pairs = jc.local_remote_pairs + self.remote_side = jc.remote_columns + self.local_columns = jc.local_columns + self.synchronize_pairs = jc.synchronize_pairs + self._calculated_foreign_keys = jc.foreign_key_columns + self.secondary_synchronize_pairs = jc.secondary_synchronize_pairs + + def _check_conflicts(self): + """Test that this relationship is legal, warn about + inheritance conflicts.""" + + if not self.is_primary() \ + and not mapperlib.class_mapper( + self.parent.class_, + configure=False).has_property(self.key): + raise sa_exc.ArgumentError("Attempting to assign a new " + "relationship '%s' to a non-primary mapper on " + "class '%s'. New relationships can only be added " + "to the primary mapper, i.e. the very first mapper " + "created for class '%s' " % (self.key, + self.parent.class_.__name__, + self.parent.class_.__name__)) + + # check for conflicting relationship() on superclass + if not self.parent.concrete: + for inheriting in self.parent.iterate_to_root(): + if inheriting is not self.parent \ + and inheriting.has_property(self.key): + util.warn("Warning: relationship '%s' on mapper " + "'%s' supersedes the same relationship " + "on inherited mapper '%s'; this can " + "cause dependency issues during flush" + % (self.key, self.parent, inheriting)) + + def _get_cascade(self): + """Return the current cascade setting for this + :class:`.RelationshipProperty`. + """ + return self._cascade + + def _set_cascade(self, cascade): + cascade = CascadeOptions(cascade) + if 'mapper' in self.__dict__: + self._check_cascade_settings(cascade) + self._cascade = cascade + + if self._dependency_processor: + self._dependency_processor.cascade = cascade + + cascade = property(_get_cascade, _set_cascade) + + def _check_cascade_settings(self, cascade): + if cascade.delete_orphan and not self.single_parent \ + and (self.direction is MANYTOMANY or self.direction + is MANYTOONE): + raise sa_exc.ArgumentError( + 'On %s, delete-orphan cascade is not supported ' + 'on a many-to-many or many-to-one relationship ' + 'when single_parent is not set. Set ' + 'single_parent=True on the relationship().' + % self) + if self.direction is MANYTOONE and self.passive_deletes: + util.warn("On %s, 'passive_deletes' is normally configured " + "on one-to-many, one-to-one, many-to-many " + "relationships only." + % self) + + if self.passive_deletes == 'all' and \ + ("delete" in cascade or + "delete-orphan" in cascade): + raise sa_exc.ArgumentError( + "On %s, can't set passive_deletes='all' in conjunction " + "with 'delete' or 'delete-orphan' cascade" % self) + + if cascade.delete_orphan: + self.mapper.primary_mapper()._delete_orphans.append( + (self.key, self.parent.class_) + ) + + def _columns_are_mapped(self, *cols): + """Return True if all columns in the given collection are + mapped by the tables referenced by this :class:`.Relationship`. + + """ + for c in cols: + if self.secondary is not None \ + and self.secondary.c.contains_column(c): + continue + if not self.parent.mapped_table.c.contains_column(c) and \ + not self.target.c.contains_column(c): + return False + return True + + def _generate_backref(self): + """Interpret the 'backref' instruction to create a + :func:`.relationship` complementary to this one.""" + + if not self.is_primary(): + return + if self.backref is not None and not self.back_populates: + if isinstance(self.backref, str): + backref_key, kwargs = self.backref, {} + else: + backref_key, kwargs = self.backref + mapper = self.mapper.primary_mapper() + + check = set(mapper.iterate_to_root()).\ + union(mapper.self_and_descendants) + for m in check: + if m.has_property(backref_key): + raise sa_exc.ArgumentError("Error creating backref " + "'%s' on relationship '%s': property of that " + "name exists on mapper '%s'" % (backref_key, + self, m)) + + # determine primaryjoin/secondaryjoin for the + # backref. Use the one we had, so that + # a custom join doesn't have to be specified in + # both directions. + if self.secondary is not None: + # for many to many, just switch primaryjoin/ + # secondaryjoin. use the annotated + # pj/sj on the _join_condition. + pj = kwargs.pop('primaryjoin', + self._join_condition.secondaryjoin_minus_local) + sj = kwargs.pop('secondaryjoin', + self._join_condition.primaryjoin_minus_local) + else: + pj = kwargs.pop('primaryjoin', + self._join_condition.primaryjoin_reverse_remote) + sj = kwargs.pop('secondaryjoin', None) + if sj: + raise sa_exc.InvalidRequestError( + "Can't assign 'secondaryjoin' on a backref " + "against a non-secondary relationship." + ) + + foreign_keys = kwargs.pop('foreign_keys', + self._user_defined_foreign_keys) + parent = self.parent.primary_mapper() + kwargs.setdefault('viewonly', self.viewonly) + kwargs.setdefault('post_update', self.post_update) + kwargs.setdefault('passive_updates', self.passive_updates) + self.back_populates = backref_key + relationship = RelationshipProperty( + parent, self.secondary, + pj, sj, + foreign_keys=foreign_keys, + back_populates=self.key, + **kwargs) + mapper._configure_property(backref_key, relationship) + + if self.back_populates: + self._add_reverse_property(self.back_populates) + + def _post_init(self): + if self.uselist is None: + self.uselist = self.direction is not MANYTOONE + if not self.viewonly: + self._dependency_processor = \ + dependency.DependencyProcessor.from_relationship(self) + + @util.memoized_property + def _use_get(self): + """memoize the 'use_get' attribute of this RelationshipLoader's + lazyloader.""" + + strategy = self._get_strategy(self._lazy_strategy) + return strategy.use_get + + @util.memoized_property + def _is_self_referential(self): + return self.mapper.common_parent(self.parent) + + def _create_joins(self, source_polymorphic=False, + source_selectable=None, dest_polymorphic=False, + dest_selectable=None, of_type=None): + if source_selectable is None: + if source_polymorphic and self.parent.with_polymorphic: + source_selectable = self.parent._with_polymorphic_selectable + + aliased = False + if dest_selectable is None: + if dest_polymorphic and self.mapper.with_polymorphic: + dest_selectable = self.mapper._with_polymorphic_selectable + aliased = True + else: + dest_selectable = self.mapper.mapped_table + + if self._is_self_referential and source_selectable is None: + dest_selectable = dest_selectable.alias() + aliased = True + else: + aliased = True + + dest_mapper = of_type or self.mapper + + single_crit = dest_mapper._single_table_criterion + aliased = aliased or (source_selectable is not None) + + primaryjoin, secondaryjoin, secondary, target_adapter, dest_selectable = \ + self._join_condition.join_targets( + source_selectable, dest_selectable, aliased, single_crit + ) + if source_selectable is None: + source_selectable = self.parent.local_table + if dest_selectable is None: + dest_selectable = self.mapper.local_table + return (primaryjoin, secondaryjoin, source_selectable, + dest_selectable, secondary, target_adapter) + def _annotate_columns(element, annotations): def clone(elem): if isinstance(elem, expression.ColumnClause): @@ -901,4 +2483,4 @@ class _ColInAnnotations(object): self.name = name def __call__(self, c): - return self.name in c._annotations \ No newline at end of file + return self.name in c._annotations -- cgit v1.2.1 From 1b25ed907fb7311d28d2273c9b9858b50c1a7afc Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 6 Oct 2013 20:29:08 -0400 Subject: - merge ticket_1418 branch, [ticket:1418] - The system of loader options has been entirely rearchitected to build upon a much more comprehensive base, the :class:`.Load` object. This base allows any common loader option like :func:`.joinedload`, :func:`.defer`, etc. to be used in a "chained" style for the purpose of specifying options down a path, such as ``joinedload("foo").subqueryload("bar")``. The new system supersedes the usage of dot-separated path names, multiple attributes within options, and the usage of ``_all()`` options. - Added a new load option :func:`.orm.load_only`. This allows a series of column names to be specified as loading "only" those attributes, deferring the rest. --- lib/sqlalchemy/orm/relationships.py | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index f37bb8a4d..2393df26b 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -83,7 +83,7 @@ class RelationshipProperty(StrategizedProperty): """ - strategy_wildcard_key = 'relationship:*' + strategy_wildcard_key = 'relationship' _dependency_processor = None @@ -638,8 +638,7 @@ class RelationshipProperty(StrategizedProperty): if strategy_class: self.strategy_class = strategy_class else: - self.strategy_class = self._strategy_lookup(lazy=self.lazy) - self._lazy_strategy = self._strategy_lookup(lazy="select") + self.strategy_class = self._strategy_lookup(("lazy", self.lazy)) self._reverse_property = set() @@ -1149,7 +1148,7 @@ class RelationshipProperty(StrategizedProperty): alias_secondary=True): if value is not None: value = attributes.instance_state(value) - return self._get_strategy(self._lazy_strategy).lazy_clause(value, + return self._lazy_strategy.lazy_clause(value, reverse_direction=not value_is_parent, alias_secondary=alias_secondary, adapt_source=adapt_source) @@ -1361,6 +1360,8 @@ class RelationshipProperty(StrategizedProperty): self._post_init() self._generate_backref() super(RelationshipProperty, self).do_init() + self._lazy_strategy = self._get_strategy((("lazy", "select"),)) + def _process_dependent_arguments(self): """Convert incoming configuration arguments to their @@ -1602,7 +1603,7 @@ class RelationshipProperty(StrategizedProperty): """memoize the 'use_get' attribute of this RelationshipLoader's lazyloader.""" - strategy = self._get_strategy(self._lazy_strategy) + strategy = self._lazy_strategy return strategy.use_get @util.memoized_property -- cgit v1.2.1 From f00544a589d5002ddf0146706c4ba67509452ea7 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 13 Oct 2013 16:42:32 -0400 Subject: - Added new option to :func:`.relationship` ``distinct_target_key``. This enables the subquery eager loader strategy to apply a DISTINCT to the innermost SELECT subquery, to assist in the case where duplicate rows are generated by the innermost query which corresponds to this relationship (there's not yet a general solution to the issue of dupe rows within subquery eager loading, however, when joins outside of the innermost subquery produce dupes). When the flag is set to ``True``, the DISTINCT is rendered unconditionally, and when it is set to ``None``, DISTINCT is rendered if the innermost relationship targets columns that do not comprise a full primary key. The option defaults to False in 0.8 (e.g. off by default in all cases), None in 0.9 (e.g. automatic by default). Thanks to Alexander Koval for help with this. [ticket:2836] --- lib/sqlalchemy/orm/relationships.py | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index 2393df26b..dbc37a4eb 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -103,6 +103,7 @@ class RelationshipProperty(StrategizedProperty): enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, + distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, @@ -372,6 +373,27 @@ class RelationshipProperty(StrategizedProperty): or when the reference is one-to-one or a collection that is guaranteed to have one or at least one entry. + :param distinct_target_key=None: + Indicate if a "subquery" eager load should apply the DISTINCT + keyword to the innermost SELECT statement. When left as ``None``, + the DISTINCT keyword will be applied in those cases when the target + columns do not comprise the full primary key of the target table. + When set to ``True``, the DISTINCT keyword is applied to the innermost + SELECT unconditionally. + + It may be desirable to set this flag to False when the DISTINCT is + reducing performance of the innermost subquery beyond that of what + duplicate innermost rows may be causing. + + .. versionadded:: 0.8.3 - distinct_target_key allows the + subquery eager loader to apply a DISTINCT modifier to the + innermost SELECT. + + .. versionchanged:: 0.9.0 - distinct_target_key now defaults to + ``None``, so that the feature enables itself automatically for + those cases where the innermost query targets a non-unique + key. + :param join_depth: when non-``None``, an integer value indicating how many levels deep "eager" loaders should join on a self-referring or cyclical @@ -621,6 +643,7 @@ class RelationshipProperty(StrategizedProperty): self.enable_typechecks = enable_typechecks self.query_class = query_class self.innerjoin = innerjoin + self.distinct_target_key = distinct_target_key self.doc = doc self.active_history = active_history self.join_depth = join_depth -- cgit v1.2.1 From d03471708ade457135672f20497d10ed4453adea Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 13 Oct 2013 17:17:00 -0400 Subject: these are in alphabetical order --- lib/sqlalchemy/orm/relationships.py | 42 ++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 21 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index dbc37a4eb..9fc67cd38 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -283,6 +283,27 @@ class RelationshipProperty(StrategizedProperty): a class which extends :class:`.RelationshipProperty.Comparator` which provides custom SQL clause generation for comparison operations. + :param distinct_target_key=None: + Indicate if a "subquery" eager load should apply the DISTINCT + keyword to the innermost SELECT statement. When left as ``None``, + the DISTINCT keyword will be applied in those cases when the target + columns do not comprise the full primary key of the target table. + When set to ``True``, the DISTINCT keyword is applied to the innermost + SELECT unconditionally. + + It may be desirable to set this flag to False when the DISTINCT is + reducing performance of the innermost subquery beyond that of what + duplicate innermost rows may be causing. + + .. versionadded:: 0.8.3 - distinct_target_key allows the + subquery eager loader to apply a DISTINCT modifier to the + innermost SELECT. + + .. versionchanged:: 0.9.0 - distinct_target_key now defaults to + ``None``, so that the feature enables itself automatically for + those cases where the innermost query targets a non-unique + key. + :param doc: docstring which will be applied to the resulting descriptor. @@ -373,27 +394,6 @@ class RelationshipProperty(StrategizedProperty): or when the reference is one-to-one or a collection that is guaranteed to have one or at least one entry. - :param distinct_target_key=None: - Indicate if a "subquery" eager load should apply the DISTINCT - keyword to the innermost SELECT statement. When left as ``None``, - the DISTINCT keyword will be applied in those cases when the target - columns do not comprise the full primary key of the target table. - When set to ``True``, the DISTINCT keyword is applied to the innermost - SELECT unconditionally. - - It may be desirable to set this flag to False when the DISTINCT is - reducing performance of the innermost subquery beyond that of what - duplicate innermost rows may be causing. - - .. versionadded:: 0.8.3 - distinct_target_key allows the - subquery eager loader to apply a DISTINCT modifier to the - innermost SELECT. - - .. versionchanged:: 0.9.0 - distinct_target_key now defaults to - ``None``, so that the feature enables itself automatically for - those cases where the innermost query targets a non-unique - key. - :param join_depth: when non-``None``, an integer value indicating how many levels deep "eager" loaders should join on a self-referring or cyclical -- cgit v1.2.1 From f035b6e0a41238d092ea2ddd10fdd5de298ff789 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Wed, 23 Oct 2013 17:41:55 -0400 Subject: An overhaul of expression handling for special symbols particularly with conjunctions, e.g. ``None`` :func:`.expression.null` :func:`.expression.true` :func:`.expression.false`, including consistency in rendering NULL in conjunctions, "short-circuiting" of :func:`.and_` and :func:`.or_` expressions which contain boolean constants, and rendering of boolean constants and expressions as compared to "1" or "0" for backends that don't feature ``true``/``false`` constants. [ticket:2804] --- lib/sqlalchemy/orm/relationships.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index 9fc67cd38..f0b23111c 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -900,7 +900,7 @@ class RelationshipProperty(StrategizedProperty): criterion = criterion._annotate( {'no_replacement_traverse': True}) - crit = j & criterion + crit = j & sql.True_._ifnone(criterion) ex = sql.exists([1], crit, from_obj=dest).correlate_except(dest) if secondary is not None: -- cgit v1.2.1 From fe1d64473896b1e8abeb8ddb966447632c057321 Mon Sep 17 00:00:00 2001 From: Vraj Mohan Date: Tue, 12 Nov 2013 18:18:04 -0500 Subject: Fix indentation issues in docstrings --- lib/sqlalchemy/orm/relationships.py | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index f0b23111c..8296be60a 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -732,7 +732,7 @@ class RelationshipProperty(StrategizedProperty): @util.memoized_property def mapper(self): """The target :class:`.Mapper` referred to by this - :class:`.RelationshipProperty.Comparator. + :class:`.RelationshipProperty.Comparator`. This is the "target" or "remote" side of the :func:`.relationship`. @@ -1372,7 +1372,8 @@ class RelationshipProperty(StrategizedProperty): def table(self): """Return the selectable linked to this :class:`.RelationshipProperty` object's target - :class:`.Mapper`.""" + :class:`.Mapper`. + """ return self.target def do_init(self): -- cgit v1.2.1 From ace7bdbc78571619cb103d57a188fbe6aa92b627 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Thu, 12 Dec 2013 12:49:57 -0500 Subject: - Error message when a string arg sent to :func:`.relationship` which doesn't resolve to a class or mapper has been corrected to work the same way as when a non-string arg is received, which indicates the name of the relationship which had the configurational error. [ticket:2888] --- lib/sqlalchemy/orm/relationships.py | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index 8296be60a..c1cf07fbe 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -1348,23 +1348,21 @@ class RelationshipProperty(StrategizedProperty): This is a lazy-initializing static attribute. """ - if isinstance(self.argument, type): - mapper_ = mapperlib.class_mapper(self.argument, - configure=False) - elif isinstance(self.argument, mapperlib.Mapper): - mapper_ = self.argument - elif util.callable(self.argument): - - # accept a callable to suit various deferred- - # configurational schemes + if util.callable(self.argument) and \ + not isinstance(self.argument, (type, mapperlib.Mapper)): + argument = self.argument() + else: + argument = self.argument - mapper_ = mapperlib.class_mapper(self.argument(), + if isinstance(argument, type): + mapper_ = mapperlib.class_mapper(argument, configure=False) + elif isinstance(self.argument, mapperlib.Mapper): + mapper_ = argument else: raise sa_exc.ArgumentError("relationship '%s' expects " "a class or a mapper argument (received: %s)" - % (self.key, type(self.argument))) - assert isinstance(mapper_, mapperlib.Mapper), mapper_ + % (self.key, type(argument))) return mapper_ @util.memoized_property -- cgit v1.2.1 From 638c1c46b23273e3c50638537ecfec91e839253e Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 15 Dec 2013 20:06:27 -0500 Subject: load_on_pending is different from enable_relationship_loading and should not be superseded. both have a potential use. --- lib/sqlalchemy/orm/relationships.py | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index c1cf07fbe..c0004e742 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -448,10 +448,6 @@ class RelationshipProperty(StrategizedProperty): :param load_on_pending=False: Indicates loading behavior for transient or pending parent objects. - .. versionchanged:: 0.8 - load_on_pending is superseded by - :meth:`.Session.enable_relationship_loading`. - When set to ``True``, causes the lazy-loader to issue a query for a parent object that is not persistent, meaning it has never been flushed. This may take effect for a pending object when @@ -467,6 +463,12 @@ class RelationshipProperty(StrategizedProperty): .. versionadded:: 0.6.5 + .. seealso:: + + :meth:`.Session.load_on_pending` - this method establishes + "load on pending" behavior for the whole object, and also allows + loading on objects that remain transient or detached. + :param order_by: indicates the ordering that should be applied when loading these items. ``order_by`` is expected to refer to one of the :class:`.Column` -- cgit v1.2.1 From 015e804c4889cac8a0423168ec7036fb5f42fea0 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Mon, 16 Dec 2013 14:35:51 -0500 Subject: wrong method name --- lib/sqlalchemy/orm/relationships.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index c0004e742..a4d1d43e3 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -465,7 +465,7 @@ class RelationshipProperty(StrategizedProperty): .. seealso:: - :meth:`.Session.load_on_pending` - this method establishes + :meth:`.Session.enable_relationship_loading` - this method establishes "load on pending" behavior for the whole object, and also allows loading on objects that remain transient or detached. -- cgit v1.2.1 From 6d3e563a575bcdc57c966980abc5038337505566 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Thu, 2 Jan 2014 18:59:26 -0500 Subject: - Fixed regression where we don't check the given name against the correct string class when setting up a backref based on a name, therefore causing the error "too many values to unpack". This was related to the Py3k conversion. [ticket:2901] --- lib/sqlalchemy/orm/relationships.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index a4d1d43e3..da402fbf3 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -1560,7 +1560,7 @@ class RelationshipProperty(StrategizedProperty): if not self.is_primary(): return if self.backref is not None and not self.back_populates: - if isinstance(self.backref, str): + if isinstance(self.backref, util.string_types): backref_key, kwargs = self.backref, {} else: backref_key, kwargs = self.backref -- cgit v1.2.1 From f89d4d216bd7605c920b7b8a10ecde6bfea2238c Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 5 Jan 2014 16:57:05 -0500 Subject: - happy new year --- lib/sqlalchemy/orm/relationships.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index da402fbf3..982f10a4d 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -1,5 +1,5 @@ # orm/relationships.py -# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors +# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php -- cgit v1.2.1 From bd74f81bb5b1158a1bc0a44e9990d4584380c481 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Mon, 13 Jan 2014 17:53:37 -0500 Subject: - Fixed a bug involving the new flattened JOIN structures which are used with :func:`.joinedload()` (thereby causing a regression in joined eager loading) as well as :func:`.aliased` in conjunction with the ``flat=True`` flag and joined-table inheritance; basically multiple joins across a "parent JOIN sub" entity using different paths to get to a target class wouldn't form the correct ON conditions. An adjustment / simplification made in the mechanics of figuring out the "left side" of the join in the case of an aliased, joined-inh class repairs the issue. [ticket:2908] --- lib/sqlalchemy/orm/relationships.py | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'lib/sqlalchemy/orm/relationships.py') diff --git a/lib/sqlalchemy/orm/relationships.py b/lib/sqlalchemy/orm/relationships.py index 982f10a4d..6fdedd382 100644 --- a/lib/sqlalchemy/orm/relationships.py +++ b/lib/sqlalchemy/orm/relationships.py @@ -747,11 +747,10 @@ class RelationshipProperty(StrategizedProperty): return self.property.parent def _source_selectable(self): - elem = self.property.parent._with_polymorphic_selectable - if self.adapter: - return self.adapter(elem) + if self._adapt_to_entity: + return self._adapt_to_entity.selectable else: - return elem + return self.property.parent._with_polymorphic_selectable def __clause_element__(self): adapt_from = self._source_selectable() -- cgit v1.2.1