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Fixed #7181 -- when ordering by a potentially NULL field, use a left-outer join 

so that the ordering doesn't accidentally restrict the result set.

(Ironically, one existing test actually showed this problem, but I was too
dumb to notice the result was incorrect.)


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7761 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick 2008-06-26 06:50:22 +00:00
parent e41df5adcc
commit ba015e0a79
2 changed files with 11 additions and 1 deletions
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4
django/db/models/sql/query.py
View File

@ -610,6 +610,10 @@ class Query(object):
alias = joins[-1] alias = joins[-1]
col = target.column col = target.column
# Must use left outer joins for nullable fields.
for join in joins:
self.promote_alias(join)
# If we get to this point and the field is a relation to another model, # If we get to this point and the field is a relation to another model,
# append the default ordering for that model. # append the default ordering for that model.
if field.rel and len(joins) > 1 and opts.ordering: if field.rel and len(joins) > 1 and opts.ordering:

8
tests/regressiontests/queries/models.py
View File

@ -499,7 +499,7 @@ FieldError: Infinite loop caused by ordering.
# Ordering by a many-valued attribute (e.g. a many-to-many or reverse # Ordering by a many-valued attribute (e.g. a many-to-many or reverse
# ForeignKey) is legal, but the results might not make sense. That isn't # ForeignKey) is legal, but the results might not make sense. That isn't
# Django's problem. Garbage in, garbage out. # Django's problem. Garbage in, garbage out.
>>> Item.objects.all().order_by('tags', 'id') >>> Item.objects.filter(tags__isnull=False).order_by('tags', 'id')
[<Item: one>, <Item: two>, <Item: one>, <Item: two>, <Item: four>] [<Item: one>, <Item: two>, <Item: one>, <Item: two>, <Item: four>]
# If we replace the default ordering, Django adjusts the required tables # If we replace the default ordering, Django adjusts the required tables
@ -762,5 +762,11 @@ Bug #7076 -- excluding shouldn't eliminate NULL entries.
>>> Tag.objects.exclude(parent__name=t1.name) >>> Tag.objects.exclude(parent__name=t1.name)
[<Tag: t1>, <Tag: t4>, <Tag: t5>] [<Tag: t1>, <Tag: t4>, <Tag: t5>]
Bug #7181 -- ordering by related tables should accomodate nullable fields (this
test is a little tricky, since NULL ordering is database dependent. Instead, we
just count the number of results).
>>> len(Tag.objects.order_by('parent__name'))
5
"""} """}