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parallel-library/vendor/sqlalchemy/orm/properties.py

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Initial Fork from https://bitbucket.org/raphaelmutschler/calibreserver/
10 years ago
# orm/properties.py
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""MapperProperty implementations.
This is a private module which defines the behavior of invidual ORM-
mapped attributes.
"""
from .. import sql, util, log, exc as sa_exc, inspect
from ..sql import operators, expression
from . import (
attributes, mapper,
strategies, configure_mappers, relationships,
dependency
)
from .util import CascadeOptions, \
_orm_annotate, _orm_deannotate, _orm_full_deannotate
from .interfaces import MANYTOMANY, MANYTOONE, ONETOMANY,\
PropComparator, StrategizedProperty
mapperlib = util.importlater("sqlalchemy.orm", "mapperlib")
NoneType = type(None)
from descriptor_props import CompositeProperty, SynonymProperty, \
ComparableProperty, ConcreteInheritedProperty
__all__ = ['ColumnProperty', 'CompositeProperty', 'SynonymProperty',
'ComparableProperty', 'RelationshipProperty', 'RelationProperty']
class ColumnProperty(StrategizedProperty):
"""Describes an object attribute that corresponds to a table column.
Public constructor is the :func:`.orm.column_property` function.
"""
def __init__(self, *columns, **kwargs):
"""Construct a ColumnProperty.
Note the public constructor is the :func:`.orm.column_property`
function.
:param \*columns: The list of `columns` describes a single
object property. If there are multiple tables joined
together for the mapper, this list represents the equivalent
column as it appears across each table.
:param group:
:param deferred:
:param comparator_factory:
:param descriptor:
:param expire_on_flush:
:param extension:
:param info: Optional data dictionary which will be populated into the
:attr:`.info` attribute of this object.
"""
self._orig_columns = [expression._labeled(c) for c in columns]
self.columns = [expression._labeled(_orm_full_deannotate(c))
for c in columns]
self.group = kwargs.pop('group', None)
self.deferred = kwargs.pop('deferred', False)
self.instrument = kwargs.pop('_instrument', True)
self.comparator_factory = kwargs.pop('comparator_factory',
self.__class__.Comparator)
self.descriptor = kwargs.pop('descriptor', None)
self.extension = kwargs.pop('extension', None)
self.active_history = kwargs.pop('active_history', False)
self.expire_on_flush = kwargs.pop('expire_on_flush', True)
if 'info' in kwargs:
self.info = kwargs.pop('info')
if 'doc' in kwargs:
self.doc = kwargs.pop('doc')
else:
for col in reversed(self.columns):
doc = getattr(col, 'doc', None)
if doc is not None:
self.doc = doc
break
else:
self.doc = None
if kwargs:
raise TypeError(
"%s received unexpected keyword argument(s): %s" % (
self.__class__.__name__,
', '.join(sorted(kwargs.keys()))))
util.set_creation_order(self)
if not self.instrument:
self.strategy_class = strategies.UninstrumentedColumnLoader
elif self.deferred:
self.strategy_class = strategies.DeferredColumnLoader
else:
self.strategy_class = strategies.ColumnLoader
@property
def expression(self):
"""Return the primary column or expression for this ColumnProperty.
"""
return self.columns[0]
def instrument_class(self, mapper):
if not self.instrument:
return
attributes.register_descriptor(
mapper.class_,
self.key,
comparator=self.comparator_factory(self, mapper),
parententity=mapper,
doc=self.doc
)
def do_init(self):
super(ColumnProperty, self).do_init()
if len(self.columns) > 1 and \
set(self.parent.primary_key).issuperset(self.columns):
util.warn(
("On mapper %s, primary key column '%s' is being combined "
"with distinct primary key column '%s' in attribute '%s'. "
"Use explicit properties to give each column its own mapped "
"attribute name.") % (self.parent, self.columns[1],
self.columns[0], self.key))
def copy(self):
return ColumnProperty(
deferred=self.deferred,
group=self.group,
active_history=self.active_history,
*self.columns)
def _getcommitted(self, state, dict_, column,
passive=attributes.PASSIVE_OFF):
return state.get_impl(self.key).\
get_committed_value(state, dict_, passive=passive)
def merge(self, session, source_state, source_dict, dest_state,
dest_dict, load, _recursive):
if not self.instrument:
return
elif self.key in source_dict:
value = source_dict[self.key]
if not load:
dest_dict[self.key] = value
else:
impl = dest_state.get_impl(self.key)
impl.set(dest_state, dest_dict, value, None)
elif dest_state.has_identity and self.key not in dest_dict:
dest_state._expire_attributes(dest_dict, [self.key])
class Comparator(PropComparator):
"""Produce boolean, comparison, and other operators for
:class:`.ColumnProperty` attributes.
See the documentation for :class:`.PropComparator` for a brief
overview.
See also:
:class:`.PropComparator`
:class:`.ColumnOperators`
:ref:`types_operators`
:attr:`.TypeEngine.comparator_factory`
"""
@util.memoized_instancemethod
def __clause_element__(self):
if self.adapter:
return self.adapter(self.prop.columns[0])
else:
return self.prop.columns[0]._annotate({
"parententity": self._parentmapper,
"parentmapper": self._parentmapper})
@util.memoized_property
def info(self):
ce = self.__clause_element__()
try:
return ce.info
except AttributeError:
return self.prop.info
def __getattr__(self, key):
"""proxy attribute access down to the mapped column.
this allows user-defined comparison methods to be accessed.
"""
return getattr(self.__clause_element__(), key)
def operate(self, op, *other, **kwargs):
return op(self.__clause_element__(), *other, **kwargs)
def reverse_operate(self, op, other, **kwargs):
col = self.__clause_element__()
return op(col._bind_param(op, other), col, **kwargs)
# TODO: legacy..do we need this ? (0.5)
ColumnComparator = Comparator
def __str__(self):
return str(self.parent.class_.__name__) + "." + self.key
log.class_logger(ColumnProperty)
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,
distinct_target_key=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):
self.uselist = uselist
self.argument = argument
self.secondary = secondary
self.primaryjoin = primaryjoin
self.secondaryjoin = secondaryjoin
self.post_update = post_update
self.direction = None
self.viewonly = viewonly
self.lazy = lazy
self.single_parent = single_parent
self._user_defined_foreign_keys = foreign_keys
self.collection_class = collection_class
self.passive_deletes = passive_deletes
self.cascade_backrefs = cascade_backrefs
self.passive_updates = passive_updates
self.remote_side = remote_side
self.enable_typechecks = enable_typechecks
self.query_class = query_class
self.innerjoin = innerjoin
self.distinct_target_key = distinct_target_key
self.doc = doc
self.active_history = active_history
self.join_depth = join_depth
self.local_remote_pairs = _local_remote_pairs
self.extension = extension
self.load_on_pending = load_on_pending
self.comparator_factory = comparator_factory or \
RelationshipProperty.Comparator
self.comparator = self.comparator_factory(self, None)
util.set_creation_order(self)
if info is not None:
self.info = info
if strategy_class:
self.strategy_class = strategy_class
elif self.lazy == 'dynamic':
from sqlalchemy.orm import dynamic
self.strategy_class = dynamic.DynaLoader
else:
self.strategy_class = strategies.factory(self.lazy)
self._reverse_property = set()
self.cascade = cascade if cascade is not False \
else "save-update, merge"
self.order_by = order_by
self.back_populates = back_populates
if self.back_populates:
if backref:
raise sa_exc.ArgumentError(
"backref and back_populates keyword arguments "
"are mutually exclusive")
self.backref = None
else:
self.backref = backref
def instrument_class(self, mapper):
attributes.register_descriptor(
mapper.class_,
self.key,
comparator=self.comparator_factory(self, mapper),
parententity=mapper,
doc=self.doc,
)
class Comparator(PropComparator):
"""Produce boolean, comparison, and other operators for
:class:`.RelationshipProperty` attributes.
See the documentation for :class:`.PropComparator` for a brief overview
of ORM level operator definition.
See also:
:class:`.PropComparator`
:class:`.ColumnProperty.Comparator`
:class:`.ColumnOperators`
:ref:`types_operators`
:attr:`.TypeEngine.comparator_factory`
"""
_of_type = None
def __init__(self, prop, parentmapper, of_type=None, adapter=None):
"""Construction of :class:`.RelationshipProperty.Comparator`
is internal to the ORM's attribute mechanics.
"""
self.prop = prop
self._parentmapper = parentmapper
self.adapter = adapter
if of_type:
self._of_type = of_type
def adapted(self, adapter):
"""Return a copy of this PropComparator which will use the
given adaption function on the local side of generated
expressions.
"""
return self.__class__(self.property, self._parentmapper,
getattr(self, '_of_type', None),
adapter)
@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,
cls, adapter=self.adapter)
def in_(self, other):
"""Produce an IN clause - this is not implemented
for :func:`~.orm.relationship`-based attributes at this time.
"""
raise NotImplementedError('in_() not yet supported for '
'relationships. For a simple many-to-one, use '
'in_() against the set of foreign key values.')
__hash__ = None
def __eq__(self, other):
"""Implement the ``==`` operator.
In a many-to-one context, such as::
MyClass.some_prop == <some object>
this will typically produce a
clause such as::
mytable.related_id == <some id>
Where ``<some id>`` is the primary key of the given
object.
The ``==`` operator provides partial functionality for non-
many-to-one comparisons:
* Comparisons against collections are not supported.
Use :meth:`~.RelationshipProperty.Comparator.contains`.
* Compared to a scalar one-to-many, will produce a
clause that compares the target columns in the parent to
the given target.
* Compared to a scalar many-to-many, an alias
of the association table will be rendered as
well, forming a natural join that is part of the
main body of the query. This will not work for
queries that go beyond simple AND conjunctions of
comparisons, such as those which use OR. Use
explicit joins, outerjoins, or
:meth:`~.RelationshipProperty.Comparator.has` for
more comprehensive non-many-to-one scalar
membership tests.
* Comparisons against ``None`` given in a one-to-many
or many-to-many context produce a NOT EXISTS clause.
"""
if isinstance(other, (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 == <some id>
Where ``<some id>`` is the value of the foreign key
attribute on ``other`` which refers to the primary
key of its parent object. From this it follows that
:meth:`~.RelationshipProperty.Comparator.contains` is
very useful when used with simple one-to-many
operations.
For many-to-many operations, the behavior of
:meth:`~.RelationshipProperty.Comparator.contains`
has more caveats. The association table will be
rendered in the statement, producing an "implicit"
join, that is, includes multiple tables in the FROM
clause which are equated in the WHERE clause::
query(MyClass).filter(MyClass.contains(other))
Produces a query like::
SELECT * FROM my_table, my_association_table AS
my_association_table_1 WHERE
my_table.id = my_association_table_1.parent_id
AND my_association_table_1.child_id = <some id>
Where ``<some id>`` would be the primary key of
``other``. From the above, it is clear that
:meth:`~.RelationshipProperty.Comparator.contains`
will **not** work with many-to-many collections when
used in queries that move beyond simple AND
conjunctions, such as multiple
:meth:`~.RelationshipProperty.Comparator.contains`
expressions joined by OR. In such cases subqueries or
explicit "outer joins" will need to be used instead.
See :meth:`~.RelationshipProperty.Comparator.any` for
a less-performant alternative using EXISTS, or refer
to :meth:`.Query.outerjoin` as well as :ref:`ormtutorial_joins`
for more details on constructing outer joins.
"""
if not self.property.uselist:
raise sa_exc.InvalidRequestError(
"'contains' not implemented for scalar "
"attributes. Use ==")
clause = self.property._optimized_compare(other,
adapt_source=self.adapter)
if self.property.secondaryjoin is not None:
clause.negation_clause = \
self.__negated_contains_or_equals(other)
return clause
def __negated_contains_or_equals(self, other):
if self.property.direction == MANYTOONE:
state = attributes.instance_state(other)
def state_bindparam(x, state, col):
o = state.obj() # strong ref
return sql.bindparam(x, unique=True, callable_=lambda: \
self.property.mapper._get_committed_attr_by_column(o, col))
def adapt(col):
if self.adapter:
return self.adapter(col)
else:
return col
if self.property._use_get:
return sql.and_(*[
sql.or_(
adapt(x) != state_bindparam(adapt(x), state, y),
adapt(x) == None)
for (x, y) in self.property.local_remote_pairs])
criterion = sql.and_(*[x == y for (x, y) in
zip(
self.property.mapper.primary_key,
self.property.\
mapper.\
primary_key_from_instance(other))
])
return ~self._criterion_exists(criterion)
def __ne__(self, other):
"""Implement the ``!=`` operator.
In a many-to-one context, such as::
MyClass.some_prop != <some object>
This will typically produce a clause such as::
mytable.related_id != <some id>
Where ``<some id>`` is the primary key of the
given object.
The ``!=`` operator provides partial functionality for non-
many-to-one comparisons:
* Comparisons against collections are not supported.
Use
:meth:`~.RelationshipProperty.Comparator.contains`
in conjunction with :func:`~.expression.not_`.
* Compared to a scalar one-to-many, will produce a
clause that compares the target columns in the parent to
the given target.
* Compared to a scalar many-to-many, an alias
of the association table will be rendered as
well, forming a natural join that is part of the
main body of the query. This will not work for
queries that go beyond simple AND conjunctions of
comparisons, such as those which use OR. Use
explicit joins, outerjoins, or
:meth:`~.RelationshipProperty.Comparator.has` in
conjunction with :func:`~.expression.not_` for
more comprehensive non-many-to-one scalar
membership tests.
* Comparisons against ``None`` given in a one-to-many
or many-to-many context produce an EXISTS clause.
"""
if isinstance(other, (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.module._new_mappers:
configure_mappers()
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(strategies.LazyLoader).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_ = mapper.class_mapper(self.argument,
configure=False)
elif isinstance(self.argument, mapper.Mapper):
mapper_ = self.argument
elif util.callable(self.argument):
# accept a callable to suit various deferred-
# configurational schemes
mapper_ = mapper.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_, mapper.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 = relationships.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 mapper.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, basestring):
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(strategies.LazyLoader)
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)
PropertyLoader = RelationProperty = RelationshipProperty
log.class_logger(RelationshipProperty)