EF杂项

Context.Entry<Job>(job).State = System.Data.Entity.EntityState.Modified;//更新
//Job类型
//job对象

EF超时问题
//连接超时
Connection Timeout=60；//加在连接字符串中

//执行超时
_test.Database.CommandTimeout = 180;

EF处理 数据库中 null的问题

var query=from f in db.tb_flag
where Nullable<int>.Equals(f.flag,null) select f; 

//生成的SQL语句为 where flag is null

//将连接字符串写在程式中

        public Context()//上下文的构造函数中直接写上对应信息,然后就可以删除app.config/web.config
            : base("server=WAYLIPC;database=Programme;uid=sa;pwd=1987214li;")
        {
        }

//linq包含查寻

  List<CodeFirst.ProductReCord> tt = _context.ProductReCords.Where(o => new int[] { 1, 2,3,4,5,6  }.Contains(o.Id)).ToList();
//==sql
SELECT * FROM	 dbo.ProductReCord WHERE Id IN (1,2,3,4,5,6)

//Linq模糊查寻

     var ct=_context.ProductReCords.Where(o => o.FileName.StartsWith("a") && o.FileName.EndsWith("t")&&o.FileName .Contains("abc")).Select(o=>new {o.Id,o.FileName,o.JobNum ,o.Check_Sum});
//StartsWith  匹配开始字符串    a%
//EndsWith    匹配结束字符串    %a
//Contains    包含  %a%     
          下面是sql
SELECT 
    [Extent1].[Id] AS [Id], 
    [Extent1].[FileName] AS [FileName], 
    [Extent1].[JobNum] AS [JobNum], 
    [Extent1].[Check_Sum] AS [Check_Sum]
    FROM [dbo].[ProductReCord] AS [Extent1]
    WHERE ([Extent1].[FileName] LIKE 'a%') AND ([Extent1].[FileName] LIKE '%t') AND ([Extent1].[FileName] LIKE '%abc%')