def get_triggers(self, using):
qn = self.get_quote_name(using)
content_type = str(ContentType.objects.get_for_model(self.model).pk)
# Create a trigger that marks any updated or newly created
# instance of the model containing the denormalized field
# as dirty.
# This is only really needed if the instance was changed without
# using the ORM or if it was part of a bulk update.
# In those cases the self_save_handler won't get called by the
# pre_save signal, so we need to ensure flush() does this later.
action = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=(content_type, "NEW.%s" %
qn(self.model._meta.pk.get_attname_column()[1])))
trigger_list = [
triggers.Trigger(self.model, "after", "update", [action],
content_type, using, self.skip),
triggers.Trigger(self.model, "after", "insert", [action],
content_type, using, self.skip),
]
return trigger_list + super(CallbackDenorm,
self).get_triggers(using=using)
def get_triggers(self, using):
qn = self.get_quote_name(using)
if not self.type:
# 'resolved_model' model never got called...
raise ValueError(
"The model '%s' could not be resolved, it probably does not exist"
% self.other_model)
content_type = str(
ContentType.objects.get_for_model(self.this_model).pk)
if self.type == "forward":
# With forward relations many instances of ``this_model``
# may be related to one instance of ``other_model``
# so we need to do a nested select query in the trigger
# to find them all.
action_new = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=triggers.TriggerNestedSelect(
self.this_model._meta.pk.model._meta.db_table,
(content_type,
self.this_model._meta.pk.get_attname_column()[1]), **{
self.field.get_attname_column()[1]:
"NEW.%s" %
qn(self.other_model._meta.pk.get_attname_column()[1])
}))
action_old = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=triggers.TriggerNestedSelect(
self.this_model._meta.pk.model._meta.db_table,
(content_type,
self.this_model._meta.pk.get_attname_column()[1]), **{
self.field.get_attname_column()[1]:
"OLD.%s" %
qn(self.other_model._meta.pk.get_attname_column()[1])
}))
return [
triggers.Trigger(self.other_model, "after", "update",
[action_new], content_type, using, self.skip),
triggers.Trigger(self.other_model, "after", "insert",
[action_new], content_type, using, self.skip),
triggers.Trigger(self.other_model, "after", "delete",
[action_old], content_type, using, self.skip),
]
if self.type == "backward":
# With backward relations a change in ``other_model`` can affect
# only one or two instances of ``this_model``.
# If the ``other_model`` instance changes the value its ForeignKey
# pointing to ``this_model`` both the old and the new related instance
# are affected, otherwise only the one it is pointing to is affected.
action_new = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=triggers.TriggerNestedSelect(
self.field.model._meta.db_table,
(content_type, self.field.get_attname_column()[1]), **{
self.field.model._meta.pk.get_attname_column()[1]:
"NEW.%s" %
qn(self.other_model._meta.pk.get_attname_column()[1])
}))
action_old = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=triggers.TriggerNestedSelect(
self.field.model._meta.db_table,
(content_type, self.field.get_attname_column()[1]), **{
self.field.model._meta.pk.get_attname_column()[1]:
"OLD.%s" %
qn(self.other_model._meta.pk.get_attname_column()[1])
}))
return [
triggers.Trigger(self.other_model, "after", "update",
[action_new, action_old], content_type, using,
self.skip),
triggers.Trigger(self.other_model, "after", "insert",
[action_new], content_type, using, self.skip),
triggers.Trigger(self.other_model, "after", "delete",
[action_old], content_type, using, self.skip),
]
if "m2m" in self.type:
# The two directions of M2M relations only differ in the column
# names used in the intermediate table.
if isinstance(self.field, models.ManyToManyField):
if "forward" in self.type:
column_name = qn(self.field.m2m_column_name())
reverse_column_name = self.field.m2m_reverse_name()
if "backward" in self.type:
column_name = qn(self.field.m2m_reverse_name())
reverse_column_name = self.field.m2m_column_name()
else:
if "forward" in self.type:
column_name = qn(self.field.object_id_field_name)
reverse_column_name = self.field.rel.to._meta.pk.column
if "backward" in self.type:
column_name = qn(self.field.rel.to._meta.pk.column)
reverse_column_name = self.field.object_id_field_name
# The first part of a M2M dependency is exactly like a backward
# ForeignKey dependency. ``this_model`` is backward FK related
# to the intermediate table.
action_m2m_new = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=(
content_type,
"NEW.%s" % column_name,
))
action_m2m_old = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=(
content_type,
"OLD.%s" % column_name,
))
trigger_list = [
triggers.Trigger(self.field, "after", "update",
[action_m2m_new, action_m2m_old],
content_type, using, self.skip),
triggers.Trigger(self.field, "after", "insert",
[action_m2m_new], content_type, using,
self.skip),
triggers.Trigger(self.field, "after", "delete",
[action_m2m_old], content_type, using,
self.skip),
]
if isinstance(self.field, models.ManyToManyField):
# Additionally to the dependency on the intermediate table
# ``this_model`` is dependant on updates to the ``other_model``-
# There is no need to track insert or delete events here,
# because a relation can only be created or deleted by
# by modifying the intermediate table.
#
# Generic relations are excluded because they have the
# same m2m_table and model table.
action_new = triggers.TriggerActionInsert(
model=DirtyInstance,
columns=("content_type_id", "object_id"),
values=triggers.TriggerNestedSelect(
self.field.m2m_db_table(), (content_type, column_name),
**{
reverse_column_name:
'NEW.%s' %
qn(self.other_model._meta.pk.get_attname_column()
[1])
}))
trigger_list.append(
triggers.Trigger(self.other_model, "after", "update",
[action_new], content_type, using,
self.skip))
return trigger_list
return []
