diff --git a/src/Libs/Model.php b/src/Libs/Model.php
index e3f43a8..92a225d 100644
--- a/src/Libs/Model.php
+++ b/src/Libs/Model.php
@@ -517,7 +517,7 @@ class Model
         static::query($sql);
 
         $pk = static::$dbPrimaryKey;
-        $this->$pk = $db->lastInsertId();
+        $this->$pk ??= $db->lastInsertId();
         $this->markAsSaved();
     }