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Fixed #7539, #13067 -- Added on_delete argument to ForeignKey to control cascade behavior. Also refactored deletion for efficiency and code clarity. Many thanks to Johannes Dollinger and Michael Glassford for extensive work on the patch, and to Alex Gaynor, Russell Keith-Magee, and Jacob Kaplan-Moss for review.

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git-svn-id: http://code.djangoproject.com/svn/django/trunk@14507 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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Carl Meyer 2010-11-09 16:46:42 +00:00
parent 3ba3294c6b
commit 616b30227d
28 changed files with 850 additions and 608 deletions
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12
docs/ref/models/querysets.txt
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@ -1263,14 +1263,20 @@ For example, to delete all the entries in a particular blog::
# Delete all the entries belonging to this Blog.
>>> Entry.objects.filter(blog=b).delete()
Django emulates the SQL constraint ``ON DELETE CASCADE`` -- in other words, any
objects with foreign keys pointing at the objects to be deleted will be deleted
along with them. For example::
By default, Django's :class:`~django.db.models.ForeignKey` emulates the SQL
constraint ``ON DELETE CASCADE`` -- in other words, any objects with foreign
keys pointing at the objects to be deleted will be deleted along with them.
For example::
blogs = Blog.objects.all()
# This will delete all Blogs and all of their Entry objects.
blogs.delete()
.. versionadded:: 1.3
This cascade behavior is customizable via the
:attr:`~django.db.models.ForeignKey.on_delete` argument to the
:class:`~django.db.models.ForeignKey`.
The ``delete()`` method does a bulk delete and does not call any ``delete()``
methods on your models. It does, however, emit the
:data:`~django.db.models.signals.pre_delete` and