C# 操作Entities Framework进行增删该查

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创建本地数据库 Players 表名 Table_1
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data.Entity;namespace EF{    class Program    {        /*        static void Main(string[] args)        {            //region --实现增加的功能            Table_1 ta = new Table_1();            ta.Name = "Duke";            ta.Number = "21";            ta.Salary = "1520";            ta.Chamption = "5";            ta.Age = "39";            ta.Team = "Spark";            //实体的变化映射数据库            //创建一个上下文对象            PlayerEntities player = new PlayerEntities();            //告诉上下文给我保存实体            player.Table_1.Add(ta);                        //把所有实体的变化保存到实体中            int i = player.SaveChanges();            Console.WriteLine(i);            Console.ReadKey();            //成功执行 返回结果为 1。        }        */        //使用 初始化器实现数据的增加效果        static void Main(string[] args)        {            /*            //实例化上下文            PlayerEntities player = new PlayerEntities();                        //添加一个信息            Table_1 ta = new Table_1();            {                ta.Name = "shark";                ta.Number = "32";                ta.Salary = "3520";                ta.Chamption = "4";                ta.Age = "43";                ta.Team = "lakers";            };            //添加实体            player.Table_1.Add(ta);            //将所有实体的变化映射到数据库中去            int i = player.SaveChanges();            Console.WriteLine(i);            Console.ReadKey();            */                        //删除            Table_1 ta = new Table_1();            PlayerEntities player = new PlayerEntities();            ta.Age = "43";            player.Table_1.Attach(ta);            //Attach 用于在上下文中重新填充数据库中已存在的实体。            //SaveChanges 不会尝试将已附加的实体插入到数据库中，因为假定该实体存在于数据库中            //第一种写法            //player.Entry(ta).State = EntityState.Deleted;            //第二种写法            player.Table_1.Remove(ta);            int i = player.SaveChanges();            Console.WriteLine(i);            Console.ReadKey();                        /*            //查询            PlayerEntities player = new PlayerEntities();            foreach(var ta in player.Table_1)            {                Console.WriteLine(ta.Age + "," + ta.Name);            }            Console.ReadKey();            */            /*            //改（先查询，后修改）                        PlayerEntities player = new PlayerEntities();            Table_1 ta = new Table_1() { Age = "32", Name = "Paul" };            player.Entry(ta).State = EntityState.Modified;            player.SaveChanges();            Console.ReadKey();            */        }    }}
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