模型查询接口增加按子表字段查询

visualdev/Tnb.Vengine/Domain/VmDbProp.cs

@@ -111,7 +111,7 @@ public class VmDbProp : VmBaseProp
     /// 获取默认值文本
     /// </summary>
     /// <returns></returns>
-    public object? GetDefaultValueString()
+    public string? GetDefaultValueString()
     {
         string val = "";
         if (!required) return val;