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Fixed #14004 -- Adds documentation for QuerySet.update() method. Than…

…ks to dwillis and timo for the majority of the wording.

git-svn-id: bcc190cf-cafb-0310-a4f2-bffc1f526a37
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1 parent cf92497 commit 6400026feb034056c0d0badcadd61804f94d8afb Gabriel Hurley committed Oct 9, 2010
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  1. +25 −0 docs/ref/models/querysets.txt
@@ -1221,6 +1221,31 @@ that it will be at some point, then using ``some_query_set.exists()`` will do
more overall work (an additional query) than simply using
+.. method:: update(**kwargs)
+Performs an SQL update query for the specified fields, and returns
+the number of rows affected. The ``update()`` method is applied instantly and
+the only restriction on the :class:`QuerySet` that is updated is that it can
+only update columns in the model's main table. Filtering based on related
+fields is still possible. You cannot call ``update()`` on a
+:class:`QuerySet` that has had a slice taken or can otherwise no longer be
+For example, if you wanted to update all the entries in a particular blog
+to use the same headline::
+ >>> b = Blog.objects.get(pk=1)
+ # Update all the headlines belonging to this Blog.
+ >>> Entry.objects.select_related().filter(blog=b).update(headline='Everything is the same')
+The ``update()`` method does a bulk update and does not call any ``save()``
+methods on your models, nor does it emit the ``pre_save`` or ``post_save``
+signals (which are a consequence of calling ``save()``).
.. _field-lookups:
Field lookups

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