Made get_indexes() consistent across backends.

Fixed #15933, #18082 -- the get_indexes() method introspection was
done inconsitently depending on the backend. For example SQLite
included all the columns in the table in the returned dictionary,
while MySQL introspected also multicolumn indexes.

All backends return now consistenly only single-column indexes.

Thanks to andi for the MySQL report, and ikelly for comments on
Oracle's get_indexes() changes.

2 files changed, 13 insertions, 1 deletions

diff --git a/tests/regressiontests/introspection/models.py b/tests/regressiontests/introspection/models.py
index 3b8383e601..02a8d71549 100644
--- a/tests/regressiontests/introspection/models.py
+++ b/tests/regressiontests/introspection/models.py
@@ -7,6 +7,9 @@ class Reporter(models.Model):
     email = models.EmailField()
     facebook_user_id = models.BigIntegerField(null=True)
 
+    class Meta:
+        unique_together = ('first_name', 'last_name')
+
     def __unicode__(self):
         return u"%s %s" % (self.first_name, self.last_name)
 
@@ -19,4 +22,4 @@ class Article(models.Model):
         return self.headline
 
     class Meta:
-        ordering = ('headline',)
\ No newline at end of file
+        ordering = ('headline',)
diff --git a/tests/regressiontests/introspection/tests.py b/tests/regressiontests/introspection/tests.py
index b425b6401d..ca58f04494 100644
--- a/tests/regressiontests/introspection/tests.py
+++ b/tests/regressiontests/introspection/tests.py
@@ -137,6 +137,15 @@ class IntrospectionTests(TestCase):
         indexes = connection.introspection.get_indexes(cursor, Article._meta.db_table)
         self.assertEqual(indexes['reporter_id'], {'unique': False, 'primary_key': False})
 
+    def test_get_indexes_multicol(self):
+        """
+        Test that multicolumn indexes are not included in the introspection
+        results.
+        """
+        cursor = connection.cursor()
+        indexes = connection.introspection.get_indexes(cursor, Reporter._meta.db_table)
+        self.assertNotIn('first_name', indexes)
+        self.assertIn('id', indexes)
 
 def datatype(dbtype, description):
     """Helper to convert a data type into a string."""