zoukankan      html  css  js  c++  java
  • LinQ To Entity的增删改查(转)

    本示例程序采用Northwind 示例数据库,下面开始编写代码对Customers表进行增、删、改、查等等操作。

    1.新增Customers记录

                using (NorthwindEntities myDb = new NorthwindEntities())

                {

                    Customers customer = new Customers();

                    Random rm = new Random();

                    customer.CustomerID = "A" + rm.Next(9999).ToString();

                    customer.CompanyName = "EntLib.com Forum";

                    customer.Address = "http://www.entlib.com/";

                    myDb.AddToCustomers(customer);

                    int count = myDb.SaveChanges();

                    txtCustomerID.Text = customer.CustomerID;

                }

    2.更新Customers记录

                using (NorthwindEntities myDb = new NorthwindEntities())

                {

                    var query = from customer in myDb.Customers

                                where customer.CustomerID == txtCustomerID.Text.Trim()

                                select customer;

                    foreach (var row in query)

                    {

                        row.CompanyName = "Updated Company Name";

                    }

                    myDb.SaveChanges();

                }

    3.删除Customers记录

                using (NorthwindEntities myDb = new NorthwindEntities())

                {

                    var query = from customer in myDb.Customers

                                where customer.CustomerID == txtCustomerID.Text.Trim()

                                select customer;

                    foreach (var row in query)

                    {

                        myDb.DeleteObject(row);

                    }

                    myDb.SaveChanges();

                }

    4.查询Customers,返回所有记录

                using (NorthwindEntities myDb = new NorthwindEntities())

                {

                    dataGridView1.DataSource = myDb.Customers;

                }

    本文来自CSDN博客,转载请标明出处:http://blog.csdn.net/baobao267/archive/2010/05/27/5627763.aspx

  • 相关阅读:
    算法-经典趣题-寻找假银币
    一天一个 Linux 命令(3):cat 命令
    算法-经典趣题-青蛙过河
    常用数据库有哪些?
    SpringBoot2.0入门教程(一) 快速入门,项目构建HelloWorld示例
    一天一个 Linux 命令(2):ls 命令
    算法-经典趣题-爱因斯坦阶梯问题
    一天一个 Linux 命令(1):vim 命令
    什么是开发环境、测试环境、UAT环境、仿真环境、生产环境?
    算法-经典趣题-渔夫捕鱼
  • 原文地址:https://www.cnblogs.com/beijia/p/linq2Entity.html
Copyright © 2011-2022 走看看