Commit e17fa9e8 authored by Anssi Kääriäinen's avatar Anssi Kääriäinen
Browse files

Fixed #20091 -- Oracle null promotion for empty strings

parent a4b8a4b6

django/db/models/sql/query.py

+8 −0
Original line number Diff line number Diff line
@@ -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)):

tests/queries/tests.py

+8 −1
Original line number Diff line number Diff line
@@ -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")),

            ['<Annotation: a1>']
@@ -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))