EF 批量更新删除(linq篇)

刚开始用EF很多东西都不会用，事后想想都很简单的东西总是用很麻烦的方式实现

1：  EF的联合查询 inner join 

　　很久很久以前我是这么写一个列表展示的，其中有两个字段Contractor和Maintaniner是需要inner join 链接查询，

　　但是当时太年轻不会用ef的链接，所以用了最笨的方法，代码如下

      [Permission("L_Business")]
        public ActionResult Index(BusinessRequest request)
        {
            //合作商户列表展示
            var result = this.MMService.GetBusinessList(request);
            result = this.GetContractorName(result);
            result = this.GetMaintainerName(result);
            return View(result);
        }
        /// <summary>
        /// 获取创建者姓名
        /// </summary>
        /// <param name="result"></param>
        /// <returns></returns>
        private IEnumerable<Business> GetContractorName(IEnumerable<Business> result)
        {
            foreach (var item in result)
            {
                var staff = this.OAService.GetStaff(item.ContractorID);
                if (staff != null) item.ConractorName = staff.Name;
            }
            return result;
        }
        /// <summary>
        /// 获取创建者姓名
        /// </summary>
        /// <param name="result"></param>
        /// <returns></returns>
        private IEnumerable<Business> GetMaintainerName(IEnumerable<Business> result)
        {
            foreach (var item in result)
            {
                var staff = this.OAService.GetStaff(item.MaintainerID);
                if (staff != null) item.MaintainerName = staff.Name;
            }
            return result;
        }    

代码很傻，需要循环多次去查出来每行中的Contractor和Maintaniner，这样是很影响效率，同时显得技术比较low的，下面的方式就好多了

首先：在model中设置链接外键

 public class Business : ModelBase
    {
  //签约人ID
        public int ContractorID { get; set; }
        //外键指明要连接的表
        [ForeignKey("ContractorID")]
        public Staff Contractor { get; set; }

        //签约日期
        public DateTime ContractDate { get; set; }
        //维护人员ID
        public int MaintainerID { get; set; }
        [ForeignKey("MaintainerID")]
        public Staff Maintainer { get; set; }
}

然后：在数据层中查询时使用Include查询

 public IEnumerable<Business> GetBusinessList(BusinessRequest request = null)
        {
            request = request ?? new BusinessRequest();
            using (var dbContext = new MMDbContext())
            {
                //include可以实现在model中设置的外检链接
                IQueryable<Business> business = dbContext.Business.Include("Contractor").Include("Maintainer");
                business = business.Where(b => b.IsDelete == );
                if (!string.IsNullOrEmpty(request.Name))
                {
                    business = business.Where(b => b.Name.Contains(request.Name));
                }
                return business.OrderByDescending(b => b.ID).ToPagedList(request.PageIndex, request.PageSize);
            }

        }

最后：在页面展示的时候

 [Permission("L_Business")]
        public ActionResult Index(BusinessRequest request)
        {
            //合作商户列表展示
            var result = this.MMService.GetBusinessList(request);

            return View(result);
        }

                        <td>
                            @(m.Contractor!=null?m.Contractor.Name:"")
                        </td>

                        <td>
                            @(m.Maintainer!=null?m.Maintainer.Name:"")
                        </td>        

但是用include 的时候用 SQL Server Profiler查看语句会发现第一个include和第二个不一样

SELECT TOP () *
FROM ( SELECT [Extent1].[ID] AS [ID1], [Extent1].[Name] AS [Name1], [Extent1].[Address] AS [Address], [Extent1].[Contact] AS [Contact], [Extent1].[Mobile] AS [Mobile1], [Extent1].[BankID] AS [BankID], [Extent1].[BankAccount] AS [BankAccount], [Extent1].[AccountName] AS [AccountName], [Extent1].[AccountNumber] AS [AccountNumber], [Extent1].[ContractorID] AS [ContractorID], [Extent1].[ContractDate] AS [ContractDate], [Extent1].[MaintainerID] AS [MaintainerID], [Extent1].[Remark] AS [Remark1], [Extent1].[Status] AS [Status], [Extent1].[IsDelete] AS [IsDelete], [Extent1].[PayStatus] AS [PayStatus], [Extent1].[Balance] AS [Balance], [Extent1].[CreateDate] AS [CreateDate1], [Extent1].[CreateStaffID] AS [CreateStaffID1], [Extent1].[CreateStaffName] AS [CreateStaffName1], [Extent2].[ID] AS [ID2], [Extent2].[Number] AS [Number1], [Extent2].[Name] AS [Name2], [Extent2].[Mobile] AS [Mobile2], [Extent2].[MobileTwo] AS [MobileTwo1], [Extent2].[Gender] AS [Gender1], [Extent2].[Phone] AS [Phone1], [Extent2].[Remark] AS [Remark2], [Extent2].[Email] AS [Email1], [Extent2].[City] AS [City1], [Extent2].[Province] AS [Province1], [Extent2].[DeleteMark] AS [DeleteMark1], [Extent2].[IsActive] AS [IsActive1], [Extent2].[IsCreateAccount] AS [IsCreateAccount1], [Extent2].[ComeInDate] AS [ComeInDate1], [Extent2].[DepartureDate] AS [DepartureDate1], [Extent2].[CompanyID] AS [CompanyID1], [Extent2].[CreateDate] AS [CreateDate2], [Extent2].[CreateStaffID] AS [CreateStaffID2], [Extent2].[CreateStaffName] AS [CreateStaffName2], [Extent3].[ID] AS [ID3], [Extent3].[Number] AS [Number2], [Extent3].[Name] AS [Name3], [Extent3].[Mobile] AS [Mobile3], [Extent3].[MobileTwo] AS [MobileTwo2], [Extent3].[Gender] AS [Gender2], [Extent3].[Phone] AS [Phone2], [Extent3].[Remark] AS [Remark3], [Extent3].[Email] AS [Email2], [Extent3].[City] AS [City2], [Extent3].[Province] AS [Province2], [Extent3].[DeleteMark] AS [DeleteMark2], [Extent3].[IsActive] AS [IsActive2], [Extent3].[IsCreateAccount] AS [IsCreateAccount2], [Extent3].[ComeInDate] AS [ComeInDate2], [Extent3].[DepartureDate] AS [DepartureDate2], [Extent3].[CompanyID] AS [CompanyID2], [Extent3].[CreateDate] AS [CreateDate3], [Extent3].[CreateStaffID] AS [CreateStaffID3], [Extent3].[CreateStaffName] AS [CreateStaffName3], row_number() OVER (ORDER BY [Extent1].[ID] DESC) AS [row_number]
    FROM   [dbo].[MM_Business] AS [Extent1]
    INNER JOIN [dbo].[OA_Staff] AS [Extent2] ON [Extent1].[ContractorID] = [Extent2].[ID]
    LEFT OUTER JOIN [dbo].[OA_Staff] AS [Extent3] ON [Extent1].[MaintainerID] = [Extent3].[ID]
    WHERE  = [Extent1].[IsDelete]
)  AS [Filter1]
WHERE [Filter1].[row_number] >
ORDER BY [Filter1].[ID1] DESC

使用  SQL Server Profiler 检测的native sql 显示 第一次的include 为 inner join 第二个为left outer join，这里是一个知识盲点，以后还要在做研究

2：EF 多次更新和删除

　图样图森破，直接上代码

        public void SaveBillAndOrder(Bill model, List<Order> orderList)
        {
            using (var dbContext = new WebSiteDbContext())
            {
                model = dbContext.Insert(model);
                //添加Order
                if (orderList.Count > )
                {
                    //增加订单，使用循环方式添加一个
                    foreach (var item in orderList)
                    {
                        var entity = dbContext.Insert(item);
                    }
                }
                dbContext.SaveChanges();
            }
        }

这里展示一个code，是我在一个多次插入的例子，还有很多是批量删除，批量更新都是用了foreach的方式

后来想，ef这么强大的工具不能就这样吧，所以开始 百度

没有包的同学可以直接nuget https://github.com/loresoft/EntityFramework.Extended

我的程序中用的是  EntityFramework.Extensions 自带的，就没有下载了

public void CancelRechargeCardPrepaymentByBillID(int BillID)
        {
            using (var dbContext = new WebSiteDbContext())
            {
                dbContext.RechargeCardPrepayments.Where(r => r.BillID == BillID).Update(r => new RechargeCardPrepayment { IsValid = (int)EnumRechargePrepaymentIsValid.WX });
                dbContext.SaveChanges();
            }
        }

实验发现效率还是可以没有出现每一条写一个insert或者update 的情况（ps:删除的话直接把Update换成Delete()就可以了）

Native sql 如下

exec sp_executesql N'UPDATE [dbo].[CRM_CardAndBalancePrepayment] SET
[IsValid] = @p__update__0
FROM [dbo].[CRM_CardAndBalancePrepayment] AS j0 INNER JOIN (
SELECT
[Extent1].[ID] AS [ID]
FROM [dbo].[CRM_CardAndBalancePrepayment] AS [Extent1]
WHERE [Extent1].[BillID] = @p__linq__0
) AS j1 ON (j0.[ID] = j1.[ID])',N'@p__linq__0 int,@p__update__0 int',@p__linq__0=143817,@p__update__0=1

写到这里脑海中突然想起了首歌：

• 其实很简单 其实很自然
• 两个人的爱由两人分担
• 其实并不难 是你太悲观
• 隔着一道墙不跟谁分享

分享出来，哈哈哈哈，