diff --git a/plugins/backward-keys.php b/plugins/backward-keys.php
index 2f3755b5..675f68ab 100644
--- a/plugins/backward-keys.php
+++ b/plugins/backward-keys.php
@@ -22,6 +22,9 @@ JOIN information_schema.referential_constraints r USING (constraint_catalog, con
 JOIN information_schema.key_column_usage t ON r.unique_constraint_catalog = t.constraint_catalog
 	AND r.unique_constraint_schema = t.constraint_schema
 	AND r.unique_constraint_name = t.constraint_name
+	AND r.constraint_catalog = t.constraint_catalog
+	AND r.constraint_schema = t.constraint_schema
+	AND r.unique_constraint_name = t.constraint_name
 	AND s.position_in_unique_constraint = t.ordinal_position
 WHERE t.table_catalog = " . Adminer\q(Adminer\DB) . " AND t.table_schema = " . Adminer\q($_GET["ns"]) . "
 AND t.table_name") . " = " . Adminer\q($table) . "