#14056: Wrong query generated when using reverse foreign key
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Reporter: premalshah | Owner: nobody
Status: new | Milestone: 1.3
Component: Database layer (models, ORM) | Version: 1.0
Resolution: | Keywords: foreign key
Stage: Unreviewed | Has_patch: 0
Needs_docs: 0 | Needs_tests: 0
Needs_better_patch: 0 |
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Changes (by premalshah):
* version: 0.96 => 1.0
Comment:
'''Clarifications on the version #:'''
I've changed the version to 1.0 since that is what Im using right now and
also because lot of people on the django IRC channel complained about the
version #. But I have seen the same behavior in 0.96, 1.1 and 1.2.
'''Clarifications for Query 1:'''
Most people on the django IRC channel said "The join is not required and
so django removes it." To concentrate on issues with Query 2 and 3, I
would agree.
'''Clarifications for Query 2:'''
There is a multi-column index on fields obj_id, field1 which speeds up the
query quite a bit. Query 2 is a query optimization issue.
'''Evidence for wrong query results for Query 3:'''
Please add this to the class called "Base"
{{{
def __str__(self):
return self.field1
}}}
Now execute this:
{{{
b = Base(field1='ABC')
b.save()
c1 = Child(obj=b, field1='a', field2=1)
c2 = Child(obj=b, field1='b', field2=2)
c3 = Child(obj=b, field1='c', field2=3)
c1.save()
c2.save()
c3.save()
Base.objects.filter(child__obj=1,
child__field1='a').order_by('child__field2', 'child__obj')
>>> [<Base: ABC>, <Base: ABC>, <Base: ABC>]
The actual result should be
>>> [<Base: ABC>]
}}}
--
Ticket URL: <http://code.djangoproject.com/ticket/14056#comment:2>
Django <http://code.djangoproject.com/>
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