Merge pull request #25 from akaariai/ticket_15933_alt

Made get_indexes() consistent across backends.

django/db/backends/__init__.py

@@ -997,6 +997,17 @@ class BaseDatabaseIntrospection(object):
         """
         raise NotImplementedError
 
+    def get_indexes(self, cursor, table_name):
+        """
+        Returns a dictionary of indexed fieldname -> infodict for the given
+        table, where each infodict is in the format:
+            {'primary_key': boolean representing whether it's the primary key,
+             'unique': boolean representing whether it's a unique index}
+
+        Only single-column indexes are introspected.
+        """
+        raise NotImplementedError
+
 class BaseDatabaseClient(object):
     """
     This class encapsulates all backend-specific methods for opening a

django/db/backends/mysql/introspection.py

@@ -85,15 +85,19 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         return None
 
     def get_indexes(self, cursor, table_name):
-        """
-        Returns a dictionary of fieldname -> infodict for the given table,
-        where each infodict is in the format:
-            {'primary_key': boolean representing whether it's the primary key,
-             'unique': boolean representing whether it's a unique index}
-        """
         cursor.execute("SHOW INDEX FROM %s" % self.connection.ops.quote_name(table_name))
+        # Do a two-pass search for indexes: on first pass check which indexes
+        # are multicolumn, on second pass check which single-column indexes
+        # are present.
+        rows = list(cursor.fetchall())
+        multicol_indexes = set()
+        for row in rows:
+            if row[3] > 1:
+                multicol_indexes.add(row[2])
         indexes = {}
-        for row in cursor.fetchall():
+        for row in rows:
+            if row[2] in multicol_indexes:
+                continue
             indexes[row[4]] = {'primary_key': (row[2] == 'PRIMARY'), 'unique': not bool(row[1])}
         return indexes
 

django/db/backends/oracle/introspection.py

@@ -72,14 +72,14 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
     FROM   user_constraints, USER_CONS_COLUMNS ca, USER_CONS_COLUMNS cb,
            user_tab_cols ta, user_tab_cols tb
     WHERE  user_constraints.table_name = %s AND
-           ta.table_name = %s AND
+           ta.table_name = user_constraints.table_name AND
            ta.column_name = ca.column_name AND
-           ca.table_name = %s AND
+           ca.table_name = ta.table_name AND
            user_constraints.constraint_name = ca.constraint_name AND
            user_constraints.r_constraint_name = cb.constraint_name AND
            cb.table_name = tb.table_name AND
            cb.column_name = tb.column_name AND
-           ca.position = cb.position""", [table_name, table_name, table_name])
+           ca.position = cb.position""", [table_name])
 
         relations = {}
         for row in cursor.fetchall():
@@ -87,36 +87,31 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         return relations
 
     def get_indexes(self, cursor, table_name):
-        """
+        sql = """
-        Returns a dictionary of fieldname -> infodict for the given table,
+    SELECT LOWER(uic1.column_name) AS column_name,
-        where each infodict is in the format:
-            {'primary_key': boolean representing whether it's the primary key,
-             'unique': boolean representing whether it's a unique index}
-        """
-        # This query retrieves each index on the given table, including the
-        # first associated field name
-        # "We were in the nick of time; you were in great peril!"
-        sql = """\
-SELECT LOWER(all_tab_cols.column_name) AS column_name,
            CASE user_constraints.constraint_type
                WHEN 'P' THEN 1 ELSE 0
            END AS is_primary_key,
            CASE user_indexes.uniqueness
                WHEN 'UNIQUE' THEN 1 ELSE 0
            END AS is_unique
-FROM   all_tab_cols, user_cons_columns, user_constraints, user_ind_columns, user_indexes
+    FROM   user_constraints, user_indexes, user_ind_columns uic1
-WHERE  all_tab_cols.column_name = user_cons_columns.column_name (+)
+    WHERE  user_constraints.constraint_type (+) = 'P'
-  AND  all_tab_cols.table_name = user_cons_columns.table_name (+)
+      AND  user_constraints.index_name (+) = uic1.index_name
-  AND  user_cons_columns.constraint_name = user_constraints.constraint_name (+)
-  AND  user_constraints.constraint_type (+) = 'P'
-  AND  user_ind_columns.column_name (+) = all_tab_cols.column_name
-  AND  user_ind_columns.table_name (+) = all_tab_cols.table_name
       AND  user_indexes.uniqueness (+) = 'UNIQUE'
-  AND  user_indexes.index_name (+) = user_ind_columns.index_name
+      AND  user_indexes.index_name (+) = uic1.index_name
-  AND  all_tab_cols.table_name = UPPER(%s)
+      AND  uic1.table_name = UPPER(%s)
-"""
+      AND  uic1.column_position = 1
+      AND  NOT EXISTS (
+              SELECT 1
+              FROM   user_ind_columns uic2
+              WHERE  uic2.index_name = uic1.index_name
+                AND  uic2.column_position = 2
+           )
+        """
         cursor.execute(sql, [table_name])
         indexes = {}
         for row in cursor.fetchall():
-            indexes[row[0]] = {'primary_key': row[1], 'unique': row[2]}
+            indexes[row[0]] = {'primary_key': bool(row[1]),
+                               'unique': bool(row[2])}
         return indexes

django/db/backends/postgresql_psycopg2/introspection.py

@@ -65,12 +65,6 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         return relations
 
     def get_indexes(self, cursor, table_name):
-        """
-        Returns a dictionary of fieldname -> infodict for the given table,
-        where each infodict is in the format:
-            {'primary_key': boolean representing whether it's the primary key,
-             'unique': boolean representing whether it's a unique index}
-        """
         # This query retrieves each index on the given table, including the
         # first associated field name
         cursor.execute("""

django/db/backends/sqlite3/introspection.py

@@ -133,28 +133,22 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         return key_columns
 
     def get_indexes(self, cursor, table_name):
-        """
-        Returns a dictionary of fieldname -> infodict for the given table,
-        where each infodict is in the format:
-            {'primary_key': boolean representing whether it's the primary key,
-             'unique': boolean representing whether it's a unique index}
-        """
         indexes = {}
         for info in self._table_info(cursor, table_name):
-            indexes[info['name']] = {'primary_key': info['pk'] != 0,
+            if info['pk'] != 0:
+                indexes[info['name']] = {'primary_key': True,
                                          'unique': False}
         cursor.execute('PRAGMA index_list(%s)' % self.connection.ops.quote_name(table_name))
         # seq, name, unique
         for index, unique in [(field[1], field[2]) for field in cursor.fetchall()]:
-            if not unique:
-                continue
             cursor.execute('PRAGMA index_info(%s)' % self.connection.ops.quote_name(index))
             info = cursor.fetchall()
             # Skip indexes across multiple fields
             if len(info) != 1:
                 continue
             name = info[0][2] # seqno, cid, name
-            indexes[name]['unique'] = True
+            indexes[name] = {'primary_key': False,
+                             'unique': unique}
         return indexes
 
     def get_primary_key_column(self, cursor, table_name):

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)
 

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."""