Linq to sql（九）：其它补充(三)

撤销提交

        var customer = ctx.Customers.Single(c => c.CustomerID == "AROUT");

        customer.ContactName = "zhuye";

        customer.Country = "Shanghai";

        Response.Write(string.Format("Name:{0},Country:{1}<br/>", customer.ContactName, customer.Country));

        customer = ctx.Customers.GetOriginalEntityState(customer);

        Response.Write(string.Format("Name:{0},Country:{1}<br/>", customer.ContactName, customer.Country));

       上面的代码执行效果如下：

Name:zhuye,Country:Shanghai
Name:Thomas Hardy,Country:UK

批量操作

       下面的代码会导致提交N次DELETE操作：

        var query = from c in ctx.Customers select c;

        ctx.Customers.RemoveAll(query);

        ctx.SubmitChanges();

       应该使用sql语句进行批操作：

        string sql = String.Format("delete from {0}", ctx.Mapping.GetTable(typeof(Customer)).TableName);

        ctx.ExecuteCommand(sql);

       对于批量更新操作也是同样道理。

一步一步学Linq to sql（九）：其它补充(三)

2010年05月17日 星期一 17:04

撤销提交

        var customer = ctx.Customers.Single(c => c.CustomerID == "AROUT");

        customer.ContactName = "zhuye";

        customer.Country = "Shanghai";

        Response.Write(string.Format("Name:{0},Country:{1}<br/>", customer.ContactName, customer.Country));

        customer = ctx.Customers.GetOriginalEntityState(customer);

        Response.Write(string.Format("Name:{0},Country:{1}<br/>", customer.ContactName, customer.Country));

       上面的代码执行效果如下：

Name:zhuye,Country:Shanghai
Name:Thomas Hardy,Country:UK

批量操作

       下面的代码会导致提交N次DELETE操作：

        var query = from c in ctx.Customers select c;

        ctx.Customers.RemoveAll(query);

        ctx.SubmitChanges();

       应该使用sql语句进行批操作：

        string sql = String.Format("delete from {0}", ctx.Mapping.GetTable(typeof(Customer)).TableName);

        ctx.ExecuteCommand(sql);

       对于批量更新操作也是同样道理。