diff --git a/B3ClientService/OfflinRpc/GradeAndWeightBL.cs b/B3ClientService/OfflinRpc/GradeAndWeightBL.cs
index f03ce88..14db03b 100644
--- a/B3ClientService/OfflinRpc/GradeAndWeightBL.cs
+++ b/B3ClientService/OfflinRpc/GradeAndWeightBL.cs
@@ -63,11 +63,11 @@ namespace BWP.B3ClientService.BL
         return;
 
       var update = new DQUpdateDom(typeof(CarcassFullInfo));
-      update.Columns.Add(new DQUpdateColumn("ButcherDate", null));
-      update.Columns.Add(new DQUpdateColumn("GradeTime", null));
+      update.Columns.Add(new DQUpdateColumn("ButcherDate", DQExpression.NULL));
+      update.Columns.Add(new DQUpdateColumn("GradeTime", DQExpression.NULL));
       //update.Columns.Add(new DQUpdateColumn("GradeWorker_ID", obj.));
-      update.Columns.Add(new DQUpdateColumn("Livestock_ID", null));
-      update.Columns.Add(new DQUpdateColumn("GradeWeight", null));
+      update.Columns.Add(new DQUpdateColumn("Livestock_ID", DQExpression.NULL));
+      update.Columns.Add(new DQUpdateColumn("GradeWeight", DQExpression.NULL));
       update.Where.Conditions.Add(DQCondition.EQ("ID", id));
       session.ExecuteNonQuery(update);
     }