{

                   return mEmployeeName;

              }

              set

              {

                   mEmployeeName = value;

              }

         }

     }

       聚合统计：

组件只提供一个默认的聚合统计就是基于条件Count操作，此操作并不支持分组功能。但对于其他聚合统计可以通过视图对象的方式来完成，视图对象可以完成数据分组、字段运算等复杂的统计描述。本篇文章发表于www.iyit.net(易特网络)

统计查询例程：

              //获取所有订单数

              Expression exp = new Expression(DBMapping.Orders);

              int count = exp.Count();

              //获取国家是USA所有雇员的订单数据

              count=(DBMapping.Orders.Employee ==(DBMapping.Employees.Country=="USA")).Count();

              //统计所有订单的销售金额

              SumPrice price =(SumPrice)exp.ListTo(new SumPrice())[0];

              //统计1997-7-1到1997-8-1销售金额

              price =(SumPrice)(DBMapping.Orders.OrderDate >= DateTime.Parse("1997-7-1")

                                 & DBMapping.Orders.OrderDate < DateTime.Parse("1997-8-1")).ListTo(new SumPrice())[0];

              //汇总雇员销售金额

              System.Collections.IList list = exp.ListTo(new SumPriceByGroup());

              //汇总某个国家的雇员销售金额

              list = (DBMapping.Orders.Employee ==(DBMapping.Employees.Country =="USA")).ListTo(new SumPriceByGroup());