Added a db_constraint option to ForeignKeys. (b55cde05) · Commits · Dom Sekotill / django

django/db/backends/creation.py

+1 −1

Original line number	Diff line number	Diff line
		@@ -77,7 +77,7 @@ class BaseDatabaseCreation(object):
		tablespace, inline=True)
		if tablespace_sql:
		field_output.append(tablespace_sql)
		if f.rel:
		if f.rel and f.db_constraint:
		ref_output, pending = self.sql_for_inline_foreign_key_references(
		model, f, known_models, style)
		if pending:

+5 −3

Original line number	Diff line number	Diff line
		@@ -981,9 +981,10 @@ class ForeignKey(RelatedField, Field):
		}
		description = _("Foreign Key (type determined by related field)")

		def __init__(self, to, to_field=None, rel_class=ManyToOneRel, **kwargs):
		def __init__(self, to, to_field=None, rel_class=ManyToOneRel,
		db_constraint=True, **kwargs):
		try:
		to_name = to._meta.model_name
		to._meta.model_name
		except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
		assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
		else:
		@@ -997,13 +998,14 @@ class ForeignKey(RelatedField, Field):
		if 'db_index' not in kwargs:
		kwargs['db_index'] = True

		self.db_constraint = db_constraint
		kwargs['rel'] = rel_class(to, to_field,
		related_name=kwargs.pop('related_name', None),
		limit_choices_to=kwargs.pop('limit_choices_to', None),
		parent_link=kwargs.pop('parent_link', False),
		on_delete=kwargs.pop('on_delete', CASCADE),
		)
		Field.__init__(self, **kwargs)
		super(ForeignKey, self).__init__(**kwargs)

		def get_path_info(self):
		"""

+13 −0

Original line number	Diff line number	Diff line
		@@ -1051,6 +1051,19 @@ define the details of how the relation works.
		The field on the related object that the relation is to. By default, Django
		uses the primary key of the related object.

		.. attribute:: ForeignKey.db_constraint

		Controls whether or not a constraint should be created in the database for
		this foreign key. The default is ``True``, and that's almost certainly what
		you want; setting this to ``False`` can be very bad for data integrity.
		That said, here are some scenarios where you might want to do this:

		* You have legacy data that is not valid.
		* You're sharding your database.

		If you use this, accessing a related object that doesn't exist will raise
		its ``DoesNotExist`` exception.

		.. attribute:: ForeignKey.on_delete

		When an object referenced by a :class:`ForeignKey` is deleted, Django by

+3 −0

Original line number	Diff line number	Diff line
		@@ -85,6 +85,9 @@ Minor features
		:class:`~django.http.HttpResponsePermanentRedirect` now provide an ``url``
		attribute (equivalent to the URL the response will redirect to).

		* Added the :attr:`django.db.models.ForeignKey.db_constraint`
		option.

		Backwards incompatible changes in 1.6
		=====================================

+14 −1

Original line number	Diff line number	Diff line
		@@ -86,3 +86,16 @@ class Item(models.Model):

		def __str__(self):
		return self.name


		@python_2_unicode_compatible
		class Object(models.Model):
		pass


		@python_2_unicode_compatible
		class ObjectReference(models.Model):
		obj = models.ForeignKey(Object, db_constraint=False)

		def __str__(self):
		return str(self.obj_id)