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# orm/dependency.py
# Copyright (C) 2005-2021 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
"""Relationship dependencies.
"""
from . import attributes
from . import exc
from . import sync
from . import unitofwork
from . import util as mapperutil
from .interfaces import MANYTOMANY
from .interfaces import MANYTOONE
from .interfaces import ONETOMANY
from .. import exc as sa_exc
from .. import sql
from .. import util
class DependencyProcessor(object):
def __init__(self, prop):
self.prop = prop
self.cascade = prop.cascade
self.mapper = prop.mapper
self.parent = prop.parent
self.secondary = prop.secondary
self.direction = prop.direction
self.post_update = prop.post_update
self.passive_deletes = prop.passive_deletes
self.passive_updates = prop.passive_updates
self.enable_typechecks = prop.enable_typechecks
if self.passive_deletes:
self._passive_delete_flag = attributes.PASSIVE_NO_INITIALIZE
else:
self._passive_delete_flag = attributes.PASSIVE_OFF
if self.passive_updates:
self._passive_update_flag = attributes.PASSIVE_NO_INITIALIZE
else:
self._passive_update_flag = attributes.PASSIVE_OFF
self.key = prop.key
if not self.prop.synchronize_pairs:
raise sa_exc.ArgumentError(
"Can't build a DependencyProcessor for relationship %s. "
"No target attributes to populate between parent and "
"child are present" % self.prop
)
@classmethod
def from_relationship(cls, prop):
return _direction_to_processor[prop.direction](prop)
def hasparent(self, state):
"""return True if the given object instance has a parent,
according to the ``InstrumentedAttribute`` handled by this
``DependencyProcessor``.
"""
return self.parent.class_manager.get_impl(self.key).hasparent(state)
def per_property_preprocessors(self, uow):
"""establish actions and dependencies related to a flush.
These actions will operate on all relevant states in
the aggregate.
"""
uow.register_preprocessor(self, True)
def per_property_flush_actions(self, uow):
after_save = unitofwork.ProcessAll(uow, self, False, True)
before_delete = unitofwork.ProcessAll(uow, self, True, True)
parent_saves = unitofwork.SaveUpdateAll(
uow, self.parent.primary_base_mapper
)
child_saves = unitofwork.SaveUpdateAll(
uow, self.mapper.primary_base_mapper
)
parent_deletes = unitofwork.DeleteAll(
uow, self.parent.primary_base_mapper
)
child_deletes = unitofwork.DeleteAll(
uow, self.mapper.primary_base_mapper
)
self.per_property_dependencies(
uow,
parent_saves,
child_saves,
parent_deletes,
child_deletes,
after_save,
before_delete,
)
def per_state_flush_actions(self, uow, states, isdelete):
"""establish actions and dependencies related to a flush.
These actions will operate on all relevant states
individually. This occurs only if there are cycles
in the 'aggregated' version of events.
"""
child_base_mapper = self.mapper.primary_base_mapper
child_saves = unitofwork.SaveUpdateAll(uow, child_base_mapper)
child_deletes = unitofwork.DeleteAll(uow, child_base_mapper)
# locate and disable the aggregate processors
# for this dependency
if isdelete:
before_delete = unitofwork.ProcessAll(uow, self, True, True)
before_delete.disabled = True
else:
after_save = unitofwork.ProcessAll(uow, self, False, True)
after_save.disabled = True
# check if the "child" side is part of the cycle
if child_saves not in uow.cycles:
# based on the current dependencies we use, the saves/
# deletes should always be in the 'cycles' collection
# together. if this changes, we will have to break up
# this method a bit more.
assert child_deletes not in uow.cycles
# child side is not part of the cycle, so we will link per-state
# actions to the aggregate "saves", "deletes" actions
child_actions = [(child_saves, False), (child_deletes, True)]
child_in_cycles = False
else:
child_in_cycles = True
# check if the "parent" side is part of the cycle
if not isdelete:
parent_saves = unitofwork.SaveUpdateAll(
uow, self.parent.base_mapper
)
parent_deletes = before_delete = None
if parent_saves in uow.cycles:
parent_in_cycles = True
else:
parent_deletes = unitofwork.DeleteAll(uow, self.parent.base_mapper)
parent_saves = after_save = None
if parent_deletes in uow.cycles:
parent_in_cycles = True
# now create actions /dependencies for each state.
for state in states:
# detect if there's anything changed or loaded
# by a preprocessor on this state/attribute. In the
# case of deletes we may try to load missing items here as well.
sum_ = state.manager[self.key].impl.get_all_pending(
state,
state.dict,
self._passive_delete_flag
if isdelete
else attributes.PASSIVE_NO_INITIALIZE,
)
if not sum_:
continue
if isdelete:
before_delete = unitofwork.ProcessState(uow, self, True, state)
if parent_in_cycles:
parent_deletes = unitofwork.DeleteState(uow, state)
else:
after_save = unitofwork.ProcessState(uow, self, False, state)
if parent_in_cycles:
parent_saves = unitofwork.SaveUpdateState(uow, state)
if child_in_cycles:
child_actions = []
for child_state, child in sum_:
if child_state not in uow.states:
child_action = (None, None)
else:
(deleted, listonly) = uow.states[child_state]
if deleted:
child_action = (
unitofwork.DeleteState(uow, child_state),
True,
)
else:
child_action = (
unitofwork.SaveUpdateState(uow, child_state),
False,
)
child_actions.append(child_action)
# establish dependencies between our possibly per-state
# parent action and our possibly per-state child action.
for child_action, childisdelete in child_actions:
self.per_state_dependencies(
uow,
parent_saves,
parent_deletes,
child_action,
after_save,
before_delete,
isdelete,
childisdelete,
)
def presort_deletes(self, uowcommit, states):
return False
def presort_saves(self, uowcommit, states):
return False
def process_deletes(self, uowcommit, states):
pass
def process_saves(self, uowcommit, states):
pass
def prop_has_changes(self, uowcommit, states, isdelete):
if not isdelete or self.passive_deletes:
passive = attributes.PASSIVE_NO_INITIALIZE
elif self.direction is MANYTOONE:
passive = attributes.PASSIVE_NO_FETCH_RELATED
else:
passive = attributes.PASSIVE_OFF
for s in states:
# TODO: add a high speed method
# to InstanceState which returns: attribute
# has a non-None value, or had one
history = uowcommit.get_attribute_history(s, self.key, passive)
if history and not history.empty():
return True
else:
return (
states
and not self.prop._is_self_referential
and self.mapper in uowcommit.mappers
)
def _verify_canload(self, state):
if self.prop.uselist and state is None:
raise exc.FlushError(
"Can't flush None value found in "
"collection %s" % (self.prop,)
)
elif state is not None and not self.mapper._canload(
state, allow_subtypes=not self.enable_typechecks
):
if self.mapper._canload(state, allow_subtypes=True):
raise exc.FlushError(
"Attempting to flush an item of type "
"%(x)s as a member of collection "
'"%(y)s". Expected an object of type '
"%(z)s or a polymorphic subclass of "
"this type. If %(x)s is a subclass of "
'%(z)s, configure mapper "%(zm)s" to '
"load this subtype polymorphically, or "
"set enable_typechecks=False to allow "
"any subtype to be accepted for flush. "
% {
"x": state.class_,
"y": self.prop,
"z": self.mapper.class_,
"zm": self.mapper,
}
)
else:
raise exc.FlushError(
"Attempting to flush an item of type "
"%(x)s as a member of collection "
'"%(y)s". Expected an object of type '
"%(z)s or a polymorphic subclass of "
"this type."
% {
"x": state.class_,
"y": self.prop,
"z": self.mapper.class_,
}
)
def _synchronize(self, state, child, associationrow, clearkeys, uowcommit):
raise NotImplementedError()
def _get_reversed_processed_set(self, uow):
if not self.prop._reverse_property:
return None
process_key = tuple(
sorted([self.key] + [p.key for p in self.prop._reverse_property])
)
return uow.memo(("reverse_key", process_key), set)
def _post_update(self, state, uowcommit, related, is_m2o_delete=False):
for x in related:
if not is_m2o_delete or x is not None:
uowcommit.register_post_update(
state, [r for l, r in self.prop.synchronize_pairs]
)
break
def _pks_changed(self, uowcommit, state):
raise NotImplementedError()
def __repr__(self):
return "%s(%s)" % (self.__class__.__name__, self.prop)
class OneToManyDP(DependencyProcessor):
def per_property_dependencies(
self,
uow,
parent_saves,
child_saves,
parent_deletes,
child_deletes,
after_save,
before_delete,
):
if self.post_update:
child_post_updates = unitofwork.PostUpdateAll(
uow, self.mapper.primary_base_mapper, False
)
child_pre_updates = unitofwork.PostUpdateAll(
uow, self.mapper.primary_base_mapper, True
)
uow.dependencies.update(
[
(child_saves, after_save),
(parent_saves, after_save),
(after_save, child_post_updates),
(before_delete, child_pre_updates),
(child_pre_updates, parent_deletes),
(child_pre_updates, child_deletes),
]
)
else:
uow.dependencies.update(
[
(parent_saves, after_save),
(after_save, child_saves),
(after_save, child_deletes),
(child_saves, parent_deletes),
(child_deletes, parent_deletes),
(before_delete, child_saves),
(before_delete, child_deletes),
]
)
def per_state_dependencies(
self,
uow,
save_parent,
delete_parent,
child_action,
after_save,
before_delete,
isdelete,
childisdelete,
):
if self.post_update:
child_post_updates = unitofwork.PostUpdateAll(
uow, self.mapper.primary_base_mapper, False
)
child_pre_updates = unitofwork.PostUpdateAll(
uow, self.mapper.primary_base_mapper, True
)
# TODO: this whole block is not covered
# by any tests
if not isdelete:
if childisdelete:
uow.dependencies.update(
[
(child_action, after_save),
(after_save, child_post_updates),
]
)
else:
uow.dependencies.update(
[
(save_parent, after_save),
(child_action, after_save),
(after_save, child_post_updates),
]
)
else:
if childisdelete:
uow.dependencies.update(
[
(before_delete, child_pre_updates),
(child_pre_updates, delete_parent),
]
)
else:
uow.dependencies.update(
[
(before_delete, child_pre_updates),
(child_pre_updates, delete_parent),
]
)
elif not isdelete:
uow.dependencies.update(
[
(save_parent, after_save),
(after_save, child_action),
(save_parent, child_action),
]
)
else:
uow.dependencies.update(
[(before_delete, child_action), (child_action, delete_parent)]
)
def presort_deletes(self, uowcommit, states):
# head object is being deleted, and we manage its list of
# child objects the child objects have to have their
# foreign key to the parent set to NULL
should_null_fks = (
not self.cascade.delete and not self.passive_deletes == "all"
)
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
for child in history.deleted:
if child is not None and self.hasparent(child) is False:
if self.cascade.delete_orphan:
uowcommit.register_object(child, isdelete=True)
else:
uowcommit.register_object(child)
if should_null_fks:
for child in history.unchanged:
if child is not None:
uowcommit.register_object(
child, operation="delete", prop=self.prop
)
def presort_saves(self, uowcommit, states):
children_added = uowcommit.memo(("children_added", self), set)
should_null_fks = (
not self.cascade.delete_orphan
and not self.passive_deletes == "all"
)
for state in states:
pks_changed = self._pks_changed(uowcommit, state)
if not pks_changed or self.passive_updates:
passive = attributes.PASSIVE_NO_INITIALIZE
else:
passive = attributes.PASSIVE_OFF
history = uowcommit.get_attribute_history(state, self.key, passive)
if history:
for child in history.added:
if child is not None:
uowcommit.register_object(
child,
cancel_delete=True,
operation="add",
prop=self.prop,
)
children_added.update(history.added)
for child in history.deleted:
if not self.cascade.delete_orphan:
if should_null_fks:
uowcommit.register_object(
child,
isdelete=False,
operation="delete",
prop=self.prop,
)
elif self.hasparent(child) is False:
uowcommit.register_object(
child,
isdelete=True,
operation="delete",
prop=self.prop,
)
for c, m, st_, dct_ in self.mapper.cascade_iterator(
"delete", child
):
uowcommit.register_object(st_, isdelete=True)
if pks_changed:
if history:
for child in history.unchanged:
if child is not None:
uowcommit.register_object(
child,
False,
self.passive_updates,
operation="pk change",
prop=self.prop,
)
def process_deletes(self, uowcommit, states):
# head object is being deleted, and we manage its list of
# child objects the child objects have to have their foreign
# key to the parent set to NULL this phase can be called
# safely for any cascade but is unnecessary if delete cascade
# is on.
if self.post_update or not self.passive_deletes == "all":
children_added = uowcommit.memo(("children_added", self), set)
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
for child in history.deleted:
if (
child is not None
and self.hasparent(child) is False
):
self._synchronize(
state, child, None, True, uowcommit, False
)
if self.post_update and child:
self._post_update(child, uowcommit, [state])
if self.post_update or not self.cascade.delete:
for child in set(history.unchanged).difference(
children_added
):
if child is not None:
self._synchronize(
state, child, None, True, uowcommit, False
)
if self.post_update and child:
self._post_update(
child, uowcommit, [state]
)
# technically, we can even remove each child from the
# collection here too. but this would be a somewhat
# inconsistent behavior since it wouldn't happen
# if the old parent wasn't deleted but child was moved.
def process_saves(self, uowcommit, states):
should_null_fks = (
not self.cascade.delete_orphan
and not self.passive_deletes == "all"
)
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, attributes.PASSIVE_NO_INITIALIZE
)
if history:
for child in history.added:
self._synchronize(
state, child, None, False, uowcommit, False
)
if child is not None and self.post_update:
self._post_update(child, uowcommit, [state])
for child in history.deleted:
if (
should_null_fks
and not self.cascade.delete_orphan
and not self.hasparent(child)
):
self._synchronize(
state, child, None, True, uowcommit, False
)
if self._pks_changed(uowcommit, state):
for child in history.unchanged:
self._synchronize(
state, child, None, False, uowcommit, True
)
def _synchronize(
self, state, child, associationrow, clearkeys, uowcommit, pks_changed
):
source = state
dest = child
self._verify_canload(child)
if dest is None or (
not self.post_update and uowcommit.is_deleted(dest)
):
return
if clearkeys:
sync.clear(dest, self.mapper, self.prop.synchronize_pairs)
else:
sync.populate(
source,
self.parent,
dest,
self.mapper,
self.prop.synchronize_pairs,
uowcommit,
self.passive_updates and pks_changed,
)
def _pks_changed(self, uowcommit, state):
return sync.source_modified(
uowcommit, state, self.parent, self.prop.synchronize_pairs
)
class ManyToOneDP(DependencyProcessor):
def __init__(self, prop):
DependencyProcessor.__init__(self, prop)
for mapper in self.mapper.self_and_descendants:
mapper._dependency_processors.append(DetectKeySwitch(prop))
def per_property_dependencies(
self,
uow,
parent_saves,
child_saves,
parent_deletes,
child_deletes,
after_save,
before_delete,
):
if self.post_update:
parent_post_updates = unitofwork.PostUpdateAll(
uow, self.parent.primary_base_mapper, False
)
parent_pre_updates = unitofwork.PostUpdateAll(
uow, self.parent.primary_base_mapper, True
)
uow.dependencies.update(
[
(child_saves, after_save),
(parent_saves, after_save),
(after_save, parent_post_updates),
(after_save, parent_pre_updates),
(before_delete, parent_pre_updates),
(parent_pre_updates, child_deletes),
(parent_pre_updates, parent_deletes),
]
)
else:
uow.dependencies.update(
[
(child_saves, after_save),
(after_save, parent_saves),
(parent_saves, child_deletes),
(parent_deletes, child_deletes),
]
)
def per_state_dependencies(
self,
uow,
save_parent,
delete_parent,
child_action,
after_save,
before_delete,
isdelete,
childisdelete,
):
if self.post_update:
if not isdelete:
parent_post_updates = unitofwork.PostUpdateAll(
uow, self.parent.primary_base_mapper, False
)
if childisdelete:
uow.dependencies.update(
[
(after_save, parent_post_updates),
(parent_post_updates, child_action),
]
)
else:
uow.dependencies.update(
[
(save_parent, after_save),
(child_action, after_save),
(after_save, parent_post_updates),
]
)
else:
parent_pre_updates = unitofwork.PostUpdateAll(
uow, self.parent.primary_base_mapper, True
)
uow.dependencies.update(
[
(before_delete, parent_pre_updates),
(parent_pre_updates, delete_parent),
(parent_pre_updates, child_action),
]
)
elif not isdelete:
if not childisdelete:
uow.dependencies.update(
[(child_action, after_save), (after_save, save_parent)]
)
else:
uow.dependencies.update([(after_save, save_parent)])
else:
if childisdelete:
uow.dependencies.update([(delete_parent, child_action)])
def presort_deletes(self, uowcommit, states):
if self.cascade.delete or self.cascade.delete_orphan:
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
if self.cascade.delete_orphan:
todelete = history.sum()
else:
todelete = history.non_deleted()
for child in todelete:
if child is None:
continue
uowcommit.register_object(
child,
isdelete=True,
operation="delete",
prop=self.prop,
)
t = self.mapper.cascade_iterator("delete", child)
for c, m, st_, dct_ in t:
uowcommit.register_object(st_, isdelete=True)
def presort_saves(self, uowcommit, states):
for state in states:
uowcommit.register_object(state, operation="add", prop=self.prop)
if self.cascade.delete_orphan:
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
for child in history.deleted:
if self.hasparent(child) is False:
uowcommit.register_object(
child,
isdelete=True,
operation="delete",
prop=self.prop,
)
t = self.mapper.cascade_iterator("delete", child)
for c, m, st_, dct_ in t:
uowcommit.register_object(st_, isdelete=True)
def process_deletes(self, uowcommit, states):
if (
self.post_update
and not self.cascade.delete_orphan
and not self.passive_deletes == "all"
):
# post_update means we have to update our
# row to not reference the child object
# before we can DELETE the row
for state in states:
self._synchronize(state, None, None, True, uowcommit)
if state and self.post_update:
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
self._post_update(
state, uowcommit, history.sum(), is_m2o_delete=True
)
def process_saves(self, uowcommit, states):
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, attributes.PASSIVE_NO_INITIALIZE
)
if history:
if history.added:
for child in history.added:
self._synchronize(
state, child, None, False, uowcommit, "add"
)
elif history.deleted:
self._synchronize(
state, None, None, True, uowcommit, "delete"
)
if self.post_update:
self._post_update(state, uowcommit, history.sum())
def _synchronize(
self,
state,
child,
associationrow,
clearkeys,
uowcommit,
operation=None,
):
if state is None or (
not self.post_update and uowcommit.is_deleted(state)
):
return
if (
operation is not None
and child is not None
and not uowcommit.session._contains_state(child)
):
util.warn(
"Object of type %s not in session, %s "
"operation along '%s' won't proceed"
% (mapperutil.state_class_str(child), operation, self.prop)
)
return
if clearkeys or child is None:
sync.clear(state, self.parent, self.prop.synchronize_pairs)
else:
self._verify_canload(child)
sync.populate(
child,
self.mapper,
state,
self.parent,
self.prop.synchronize_pairs,
uowcommit,
False,
)
class DetectKeySwitch(DependencyProcessor):
"""For many-to-one relationships with no one-to-many backref,
searches for parents through the unit of work when a primary
key has changed and updates them.
Theoretically, this approach could be expanded to support transparent
deletion of objects referenced via many-to-one as well, although
the current attribute system doesn't do enough bookkeeping for this
to be efficient.
"""
def per_property_preprocessors(self, uow):
if self.prop._reverse_property:
if self.passive_updates:
return
else:
if False in (
prop.passive_updates
for prop in self.prop._reverse_property
):
return
uow.register_preprocessor(self, False)
def per_property_flush_actions(self, uow):
parent_saves = unitofwork.SaveUpdateAll(uow, self.parent.base_mapper)
after_save = unitofwork.ProcessAll(uow, self, False, False)
uow.dependencies.update([(parent_saves, after_save)])
def per_state_flush_actions(self, uow, states, isdelete):
pass
def presort_deletes(self, uowcommit, states):
pass
def presort_saves(self, uow, states):
if not self.passive_updates:
# for non-passive updates, register in the preprocess stage
# so that mapper save_obj() gets a hold of changes
self._process_key_switches(states, uow)
def prop_has_changes(self, uow, states, isdelete):
if not isdelete and self.passive_updates:
d = self._key_switchers(uow, states)
return bool(d)
return False
def process_deletes(self, uowcommit, states):
assert False
def process_saves(self, uowcommit, states):
# for passive updates, register objects in the process stage
# so that we avoid ManyToOneDP's registering the object without
# the listonly flag in its own preprocess stage (results in UPDATE)
# statements being emitted
assert self.passive_updates
self._process_key_switches(states, uowcommit)
def _key_switchers(self, uow, states):
switched, notswitched = uow.memo(
("pk_switchers", self), lambda: (set(), set())
)
allstates = switched.union(notswitched)
for s in states:
if s not in allstates:
if self._pks_changed(uow, s):
switched.add(s)
else:
notswitched.add(s)
return switched
def _process_key_switches(self, deplist, uowcommit):
switchers = self._key_switchers(uowcommit, deplist)
if switchers:
# if primary key values have actually changed somewhere, perform
# a linear search through the UOW in search of a parent.
for state in uowcommit.session.identity_map.all_states():
if not issubclass(state.class_, self.parent.class_):
continue
dict_ = state.dict
related = state.get_impl(self.key).get(
state, dict_, passive=self._passive_update_flag
)
if (
related is not attributes.PASSIVE_NO_RESULT
and related is not None
):
if self.prop.uselist:
if not related:
continue
related_obj = related[0]
else:
related_obj = related
related_state = attributes.instance_state(related_obj)
if related_state in switchers:
uowcommit.register_object(
state, False, self.passive_updates
)
sync.populate(
related_state,
self.mapper,
state,
self.parent,
self.prop.synchronize_pairs,
uowcommit,
self.passive_updates,
)
def _pks_changed(self, uowcommit, state):
return bool(state.key) and sync.source_modified(
uowcommit, state, self.mapper, self.prop.synchronize_pairs
)
class ManyToManyDP(DependencyProcessor):
def per_property_dependencies(
self,
uow,
parent_saves,
child_saves,
parent_deletes,
child_deletes,
after_save,
before_delete,
):
uow.dependencies.update(
[
(parent_saves, after_save),
(child_saves, after_save),
(after_save, child_deletes),
# a rowswitch on the parent from deleted to saved
# can make this one occur, as the "save" may remove
# an element from the
# "deleted" list before we have a chance to
# process its child rows
(before_delete, parent_saves),
(before_delete, parent_deletes),
(before_delete, child_deletes),
(before_delete, child_saves),
]
)
def per_state_dependencies(
self,
uow,
save_parent,
delete_parent,
child_action,
after_save,
before_delete,
isdelete,
childisdelete,
):
if not isdelete:
if childisdelete:
uow.dependencies.update(
[(save_parent, after_save), (after_save, child_action)]
)
else:
uow.dependencies.update(
[(save_parent, after_save), (child_action, after_save)]
)
else:
uow.dependencies.update(
[(before_delete, child_action), (before_delete, delete_parent)]
)
def presort_deletes(self, uowcommit, states):
# TODO: no tests fail if this whole
# thing is removed !!!!
if not self.passive_deletes:
# if no passive deletes, load history on
# the collection, so that prop_has_changes()
# returns True
for state in states:
uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
def presort_saves(self, uowcommit, states):
if not self.passive_updates:
# if no passive updates, load history on
# each collection where parent has changed PK,
# so that prop_has_changes() returns True
for state in states:
if self._pks_changed(uowcommit, state):
history = uowcommit.get_attribute_history(
state, self.key, attributes.PASSIVE_OFF
)
if not self.cascade.delete_orphan:
return
# check for child items removed from the collection
# if delete_orphan check is turned on.
for state in states:
history = uowcommit.get_attribute_history(
state, self.key, attributes.PASSIVE_NO_INITIALIZE
)
if history:
for child in history.deleted:
if self.hasparent(child) is False:
uowcommit.register_object(
child,
isdelete=True,
operation="delete",
prop=self.prop,
)
for c, m, st_, dct_ in self.mapper.cascade_iterator(
"delete", child
):
uowcommit.register_object(st_, isdelete=True)
def process_deletes(self, uowcommit, states):
secondary_delete = []
secondary_insert = []
secondary_update = []
processed = self._get_reversed_processed_set(uowcommit)
tmp = set()
for state in states:
# this history should be cached already, as
# we loaded it in preprocess_deletes
history = uowcommit.get_attribute_history(
state, self.key, self._passive_delete_flag
)
if history:
for child in history.non_added():
if child is None or (
processed is not None and (state, child) in processed
):
continue
associationrow = {}
if not self._synchronize(
state,
child,
associationrow,
False,
uowcommit,
"delete",
):
continue
secondary_delete.append(associationrow)
tmp.update((c, state) for c in history.non_added())
if processed is not None:
processed.update(tmp)
self._run_crud(
uowcommit, secondary_insert, secondary_update, secondary_delete
)
def process_saves(self, uowcommit, states):
secondary_delete = []
secondary_insert = []
secondary_update = []
processed = self._get_reversed_processed_set(uowcommit)
tmp = set()
for state in states:
need_cascade_pks = not self.passive_updates and self._pks_changed(
uowcommit, state
)
if need_cascade_pks:
passive = attributes.PASSIVE_OFF
else:
passive = attributes.PASSIVE_NO_INITIALIZE
history = uowcommit.get_attribute_history(state, self.key, passive)
if history:
for child in history.added:
if processed is not None and (state, child) in processed:
continue
associationrow = {}
if not self._synchronize(
state, child, associationrow, False, uowcommit, "add"
):
continue
secondary_insert.append(associationrow)
for child in history.deleted:
if processed is not None and (state, child) in processed:
continue
associationrow = {}
if not self._synchronize(
state,
child,
associationrow,
False,
uowcommit,
"delete",
):
continue
secondary_delete.append(associationrow)
tmp.update((c, state) for c in history.added + history.deleted)
if need_cascade_pks:
for child in history.unchanged:
associationrow = {}
sync.update(
state,
self.parent,
associationrow,
"old_",
self.prop.synchronize_pairs,
)
sync.update(
child,
self.mapper,
associationrow,
"old_",
self.prop.secondary_synchronize_pairs,
)
secondary_update.append(associationrow)
if processed is not None:
processed.update(tmp)
self._run_crud(
uowcommit, secondary_insert, secondary_update, secondary_delete
)
def _run_crud(
self, uowcommit, secondary_insert, secondary_update, secondary_delete
):
connection = uowcommit.transaction.connection(self.mapper)
if secondary_delete:
associationrow = secondary_delete[0]
statement = self.secondary.delete(
sql.and_(
*[
c == sql.bindparam(c.key, type_=c.type)
for c in self.secondary.c
if c.key in associationrow
]
)
)
result = connection.execute(statement, secondary_delete)
if (
result.supports_sane_multi_rowcount()
) and result.rowcount != len(secondary_delete):
raise exc.StaleDataError(
"DELETE statement on table '%s' expected to delete "
"%d row(s); Only %d were matched."
% (
self.secondary.description,
len(secondary_delete),
result.rowcount,
)
)
if secondary_update:
associationrow = secondary_update[0]
statement = self.secondary.update(
sql.and_(
*[
c == sql.bindparam("old_" + c.key, type_=c.type)
for c in self.secondary.c
if c.key in associationrow
]
)
)
result = connection.execute(statement, secondary_update)
if (
result.supports_sane_multi_rowcount()
) and result.rowcount != len(secondary_update):
raise exc.StaleDataError(
"UPDATE statement on table '%s' expected to update "
"%d row(s); Only %d were matched."
% (
self.secondary.description,
len(secondary_update),
result.rowcount,
)
)
if secondary_insert:
statement = self.secondary.insert()
connection.execute(statement, secondary_insert)
def _synchronize(
self, state, child, associationrow, clearkeys, uowcommit, operation
):
# this checks for None if uselist=True
self._verify_canload(child)
# but if uselist=False we get here. If child is None,
# no association row can be generated, so return.
if child is None:
return False
if child is not None and not uowcommit.session._contains_state(child):
if not child.deleted:
util.warn(
"Object of type %s not in session, %s "
"operation along '%s' won't proceed"
% (mapperutil.state_class_str(child), operation, self.prop)
)
return False
sync.populate_dict(
state, self.parent, associationrow, self.prop.synchronize_pairs
)
sync.populate_dict(
child,
self.mapper,
associationrow,
self.prop.secondary_synchronize_pairs,
)
return True
def _pks_changed(self, uowcommit, state):
return sync.source_modified(
uowcommit, state, self.parent, self.prop.synchronize_pairs
)
_direction_to_processor = {
ONETOMANY: OneToManyDP,
MANYTOONE: ManyToOneDP,
MANYTOMANY: ManyToManyDP,
}