diff --git a/Src/Asp.Net/SqlSugar/Realization/Dm/DbMaintenance/DmDbMaintenance.cs b/Src/Asp.Net/SqlSugar/Realization/Dm/DbMaintenance/DmDbMaintenance.cs
index 38acaa554..708bcbd63 100644
--- a/Src/Asp.Net/SqlSugar/Realization/Dm/DbMaintenance/DmDbMaintenance.cs
+++ b/Src/Asp.Net/SqlSugar/Realization/Dm/DbMaintenance/DmDbMaintenance.cs
@@ -239,14 +239,14 @@ namespace SqlSugar
         {
             get
             {
-                return "";
+                return " null ";
             }
         }
         protected override string CreateTableNotNull
         {
             get
             {
-                return "";
+                return " not null ";
             }
         }
         protected override string CreateTablePirmaryKey