diff --git a/nocodetools/views.py b/nocodetools/views.py
index 839149a..3b6056c 100644
--- a/nocodetools/views.py
+++ b/nocodetools/views.py
@@ -32,7 +32,9 @@ class NoCodeToolAPIView(APIView):
 
         obj_serializer = NocodetoolObjectMapService.mapping_model_serializer(related_type)
 
-        code = Code.objects.get(id=code_id)
+        code = Code.objects.filter(id=code_id).first()
+        if not code:
+            return Response({"message": "No code object"}, status=status.HTTP_400_BAD_REQUEST)
         return Response({
                 "obj_info": obj_serializer(obj).data,
                 "codes": CodeSerializer(code).data
@@ -149,7 +151,7 @@ class NocodeToolWorkingAPIView(APIView):
             obj.now_worker = request.user.nickname
         elif action == "end":
             if obj.now_worker and obj.now_worker == request.user.nickname:
-                obj.now_worker = None
+                obj.now_worker = ''
             else:
                 return Response(
                     {