diff --git a/dbschema/default.esdl b/dbschema/default.esdl
index 760ea8e..395e85e 100644
--- a/dbschema/default.esdl
+++ b/dbschema/default.esdl
@@ -30,6 +30,7 @@ module default {
     }
     required multi moves: Moves {
       readonly := true;
+      on source delete delete target;
     }
     required single snake: Snake {
       readonly := true;