diff --git a/src/Support/Definition/RelayType.php b/src/Support/Definition/RelayType.php
index e51fc9e..c540ab5 100644
--- a/src/Support/Definition/RelayType.php
+++ b/src/Support/Definition/RelayType.php
@@ -73,7 +73,7 @@ public function getConnections()
      */
     public function getIdentifier($obj)
     {
-        return $obj->id;
+        return $obj->getKey();
     }
 
     /**