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DeleteOnSubmit与DeleteAllOnSubmit异同

2010-07-22 10:36:35| 分类：软件开发测试 | 标签： |举报 |字号大中小订阅

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a. DeleteOnSubmit: 将一个实体从datacontext对象中删除,并在SubmitChange()的时候执行更改。

b. DeleteAllOnSubmit:将一个实体集合从datacontext对象中删除,并在SubmitChange()的时候执行更改。

例：

protected void btnDelete_Click(object sender, EventArgs e)

{

UsersDataContext dal = new UsersDataContext();

User user = dal.Users.FirstOrDefault(s => s.UserName == "Tom");

if (user != null)

{

dal.Users.DeleteOnSubmit(user);//删除单条数据

}

var q = dal.Users;

dal.Users.DeleteAllOnSubmit(q);//删除数据集

dal.SubmitChanges();

}

※注：以上两个函数必须要跟随SubmitChange()函数才能从数据库中删除数据。我们可以通俗的理解为：以上两个函数仅仅相当于一条Sql语句，而SubmitChange()相当于执行此条Sql语句。

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