Linq to sql

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data.Linq;namespace ConsoleApplication1{    class Program    {        public static DataClasses1DataContext DataClass=new DataClasses1DataContext();        static void Main(string[] args)        {            //=====================查询所有========================            var Select = SelectAll();            foreach (var sel in Select)            {                Console.WriteLine(sel.name);            }            //==================查询指定条件内容==========================            aa SelectSingles = SelectSingle();            Console.WriteLine(SelectSingles.name);            //==================修改指定条件的内容========================            Update();                         //=================添加指定条件的内容========================            Insert();            //=================删除指定条件的内容========================            Delete();        }        //linq to sql查询全部        public static IEnumerable<aa> SelectAll()        {            return DataClass.aa;        }        public static aa SelectSingle()        {            return DataClass.aa.Single(x => x.name == "测试");        }        public static void Update()        {            var updates = DataClass.aa.Single(x=>x.name=="测试");            updates.name = "abc";            DataClass.SubmitChanges();//千万别忘记            Console.WriteLine("更新完成");        }        public static void Insert()        {             var a=new aa            {              name="添加"            };            DataClass.aa.InsertOnSubmit(a);            DataClass.SubmitChanges();            Console.WriteLine("添加成功");        }        public static void Delete()        {            DataClass.aa.DeleteOnSubmit(DataClass.aa.Single(x=>x.name=="测试"));            DataClass.SubmitChanges();            Console.WriteLine("删除成功");        }    }}