From e17fa9e877e84e93b699c2bd13ea48dbbb86e451 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Anssi=20K=C3=A4=C3=A4ri=C3=A4inen?= Date: Sun, 24 Mar 2013 22:59:44 +0200 Subject: [PATCH] Fixed #20091 -- Oracle null promotion for empty strings --- django/db/models/sql/query.py | 8 ++++++++ tests/queries/tests.py | 9 ++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index fb42cfc5db..acb9f248d6 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -1078,6 +1078,14 @@ class Query(object): elif isinstance(value, ExpressionNode): # If value is a query expression, evaluate it value = SQLEvaluator(value, self, reuse=can_reuse) + # For Oracle '' is equivalent to null. The check needs to be done + # at this stage because join promotion can't be done at compiler + # stage. Using DEFAULT_DB_ALIAS isn't nice, but it is the best we + # can do here. Similar thing is done in is_nullable(), too. + if (connections[DEFAULT_DB_ALIAS].features.interprets_empty_strings_as_nulls and + lookup_type == 'exact' and value == ''): + value = True + lookup_type = 'isnull' for alias, aggregate in self.aggregates.items(): if alias in (parts[0], LOOKUP_SEP.join(parts)): diff --git a/tests/queries/tests.py b/tests/queries/tests.py index 806648aa54..cdc26248c9 100644 --- a/tests/queries/tests.py +++ b/tests/queries/tests.py @@ -1785,7 +1785,6 @@ class Queries6Tests(TestCase): # Nested queries are possible (although should be used with care, since # they have performance problems on backends like MySQL. - self.assertQuerysetEqual( Annotation.objects.filter(notes__in=Note.objects.filter(note="n1")), [''] @@ -2824,3 +2823,11 @@ class Ticket20101Tests(TestCase): self.assertTrue(n in qs1) self.assertFalse(n in qs2) self.assertTrue(n in (qs1 | qs2)) + +class EmptyStringPromotionTests(TestCase): + def test_empty_string_promotion(self): + qs = RelatedObject.objects.filter(single__name='') + if connection.features.interprets_empty_strings_as_nulls: + self.assertIn('LEFT OUTER JOIN', str(qs.query)) + else: + self.assertNotIn('LEFT OUTER JOIN', str(qs.query))