linq ->sql & linq->lambda中的cud

添加

//声明一个上下文
         bookshopEntities dbContext = new bookshopEntities();

           users user = new users();
            user.loginid = "qweras123dfqwe";
            user.loginpwd = "qwer2asdfqwe";
            user.name = "qwerasdf123qwe";
            user.address = "qwerasdfqwe";
            user.phone = "qwerasdfqwe2";
            user.mail = "sss12231";
            user.userstateid = 1;
            user.userroleid = 1;
            ////告诉ef对实体执行插入操作
            dbcontext.users.add(user);
    　　　　dbContext.SaveChanges();

修改(更新)

1.修改该对象的所有属性

bookshopEntities dbContext = new bookshopEntities();         
           Users user = new Users();
            user.LoginId = "zhanssss";
            user.LoginPwd = "zhansssss";
            user.Name = "zhanssss";
            user.Address = "zhanssss";
            user.Phone = "zhanssss";
            user.Mail = "zhanssss";
            user.UserStateId = 1;

　　　　　　dbContext.SaveChanges();

user.UserRoleId = 1; user.Id = 110; dbContext.Entry<Users>(user).State = System.Data.EntityState.Modified;

2.修改该对象的一个或多个属性

Users user = new Users();
            user.LoginPwd = "412213";
            user.Id = 110;//修改任何属性都必须指定唯一主键
            dbContext.Entry<Users>(user).Property("LoginPwd").IsModified = true;
　　　　 　　//dbContext.Entry<Users>(user).Property(c => new { c.LoginPwd,c.Money});  lambda表达式简写
　　　　　　　　dbContext.SaveChanges();

批量更新

删除需()指定唯一主键)

 db.Entry<Question>(question).State=EntityState.Deleted;

或

 db.Question.Remove(question);

若需批量删除,只能一条一条删,ef已删掉批量删除的方法

   foreach (var item in temp.ToList())
            {
                db.Dtb.Remove(item);
            }