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Code Issues 32 Releases Wiki Activity

Using querysets as an rvalue in filter() calls was causing an unnecessary

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database query, due to a bool() call. This change stops that behaviour.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9715 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick
2009-01-08 05:16:21 +00:00
parent d00c013cc8
commit d068ad0c01
3 changed files with 17 additions and 0 deletions
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7
tests/regressiontests/queries/models.py
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@@ -1015,6 +1015,13 @@ performance problems on backends like MySQL.
>>> Annotation.objects.filter(notes__in=Note.objects.filter(note="n1"))
[<Annotation: a1>]
Nested queries should not evaluate the inner query as part of constructing the
SQL. This test verifies this: if the inner query is evaluated, the outer "in"
lookup will raise an EmptyResultSet exception (as the inner query returns
nothing).
>>> print Annotation.objects.filter(notes__in=Note.objects.filter(note="xyzzy")).query
SELECT ...
"""}
# In Python 2.3 and the Python 2.6 beta releases, exceptions raised in __len__