1 files changed, 21 insertions, 0 deletions
diff --git a/webapp/django/db/backends/postgresql_psycopg2/introspection.py b/webapp/django/db/backends/postgresql_psycopg2/introspection.py
new file mode 100644
index 0000000000..83bd9b4c44
--- /dev/null
+++ b/webapp/django/db/backends/postgresql_psycopg2/introspection.py
@@ -0,0 +1,21 @@
+from django.db.backends.postgresql.introspection import DatabaseIntrospection as PostgresDatabaseIntrospection
+
+class DatabaseIntrospection(PostgresDatabaseIntrospection):
+
+    def get_relations(self, cursor, table_name):
+        """
+        Returns a dictionary of {field_index: (field_index_other_table, other_table)}
+        representing all relationships to the given table. Indexes are 0-based.
+        """
+        cursor.execute("""
+            SELECT con.conkey, con.confkey, c2.relname
+            FROM pg_constraint con, pg_class c1, pg_class c2
+            WHERE c1.oid = con.conrelid
+                AND c2.oid = con.confrelid
+                AND c1.relname = %s
+                AND con.contype = 'f'""", [table_name])
+        relations = {}
+        for row in cursor.fetchall():
+            # row[0] and row[1] are single-item lists, so grab the single item.
+            relations[row[0][0] - 1] = (row[1][0] - 1, row[2])
+        return relations