Add unit test

Src/Asp.Net/SqlServerTest/Demo/DemoE_CodeFirst.cs

@@ -70,9 +70,23 @@ namespace OrmTest
             db.Insertable(new Unittest1011() { name = "a" }).ExecuteCommand();
             db.Insertable(new Unittest22221() { name = "a" }).ExecuteCommand();
             db.CodeFirst.InitTables<Unitrtqqqadfa>();
+            db.CodeFirst.InitTables<Unitrasdfafa>();
+            var id=db.Insertable(new Unitrasdfafa() { Name = "Unitrasdfafa" }).ExecuteReturnIdentity();
+            db.Updateable(new Unitrasdfafa() { Name = "Unitrasdfafa", id = id }).ExecuteCommand();
+            var xx=db.Queryable<Unitrasdfafa>().Select("*").ToDataTable();
             Console.WriteLine("#### CodeFirst end ####");
         }
     }
+
+    [SugarTable("Unitrasdfafa",Discrimator ="Type:1,Type2:2")]
+    public class Unitrasdfafa
+    {
+
+        [SugarColumn(IsIdentity =true,IsPrimaryKey =true)]
+        public int id { get; set; }
+        public string Name { get; set; }
+    }
+
     [SugarTable("dbo.Unitrtqqqadfa")]
     public class Unitrtqqqadfa
     {