上篇博客介绍了一下linq的基本理解，接下里介绍一下LINQ的增删改查

一、增加

dmtodoEntities db = new dmtodoEntities();
            t_User user = new t_User();
            user.ID = 1;
            user.UserName = "千千";
            user.Pwd = "qq";
            db.t_User.InsertOnSubmit(user);
            db.SubmitChanges();

dmtodoEntities db = new dmtodoEntities();
            t_User userDelete = (from userinfo in db.t_User where userinfo.ID == 1 select userinfo).FirstOrDefault();
            if (userDelete != null)
            {
                db.t_User.DeleteOnSubmit(userDelete);
                db.SubmitChanges();
            }

public bool update(t_labe u) 
    {
        bool b = false;
        //查找出修改前的数据
        t_label lb = db.t_labe.Where(a => a.UserName == u.UserName).FirstOrDefault();
        if (lb != null)
        {
            try
            {
            //用修改后的值给修改前的值赋值
                lb.UserName = u.UserName;
                lb.PassWord = u.PassWord;
                lb.NickName = u.NickName;
                lb.Sex = u.Sex;
                db.SubmitChanges();//执行
                b = true;
            }
            catch { }
        }
        return b;
    }

List<t_label> list = (from c in db.t_label where c.label_name == enlabel.label_name && c.user_id==enlabel.user_id select c).ToList();
            return list; 

  基本的增删改查就是这些，从数据库查询符合条件的语句，是用Lambda还是接近于SQL的语句写都可以。