diff --git a/src/app/datasources/rest/modeldefs.rest.ts b/src/app/datasources/rest/modeldefs.rest.ts
index fdb4b99..0af00ff 100644
--- a/src/app/datasources/rest/modeldefs.rest.ts
+++ b/src/app/datasources/rest/modeldefs.rest.ts
@@ -16,6 +16,7 @@
 export interface IXosModelDefsRelation {
   model: string; // model name
   type: string; // relation type
+  on_field: string; // the field that is containing the relation
 }
 
 export interface IXosModeldef {