Removed DatabaseIntrospection.get_key_columns().

Thanks Simon Charette for the report.

django/db/backends/sqlite3/introspection.py

@@ -170,35 +170,6 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
 
         return relations
 
-    def get_key_columns(self, cursor, table_name):
-        """
-        Return a list of (column_name, referenced_table_name, referenced_column_name)
-        for all key columns in given table.
-        """
-        key_columns = []
-
-        # Schema for this table
-        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
-        results = cursor.fetchone()[0].strip()
-        results = results[results.index('(') + 1:results.rindex(')')]
-
-        # Walk through and look for references to other tables. SQLite doesn't
-        # really have enforced references, but since it echoes out the SQL used
-        # to create the table we can look for REFERENCES statements used there.
-        for field_index, field_desc in enumerate(results.split(',')):
-            field_desc = field_desc.strip()
-            if field_desc.startswith("UNIQUE"):
-                continue
-
-            m = re.search(r'"(.*)".*references (.*) \(["|](.*)["|]\)', field_desc, re.I)
-            if not m:
-                continue
-
-            # This will append (column_name, referenced_table_name, referenced_column_name) to key_columns
-            key_columns.append(tuple(s.strip('"') for s in m.groups()))
-
-        return key_columns
-
     def get_primary_key_column(self, cursor, table_name):
         """Return the column name of the primary key for the given table."""
         cursor.execute(