Question

我的任务是将一些旧的SQL存储过程转换为LINQ，用于我们正在进行的EF迁移，我有点难过。鉴于这是从现有应用程序迁移，edmx首先生成数据库。所以，我有一个我试图复制的SQL语句：

SELECT DISTINCT
    d.DeliverySubscriptionId
,   d.ContactId
,   d.statementMacroId_fk
,   m.Name as MacroName
,   DeliveryMethod  =     REPLACE((SELECT DISTINCT
                                    dm2.Name + ',' AS 'data()'
                              FROM
                                    DeliverySubscription d2     
                              JOIN 
                                    StatementMacro m2 on 
                                    d2.StatementMacroId_fk = m2.StatementMacroId    
                              JOIN 
                                    DeliverySubscription_Method_Rel dmr2 ON 
                                    d2.DeliverySubscriptionId = dmr2.DeliverySubscriptionId_Fk
                              JOIN 
                                    dbo.DeliveryMethod dm2 ON 
                                    dmr2.DeliveryMethodId_Fk = dm2.DeliveryMethodId
                              WHERE
                                    d.DeliveryConfigurationId_fk = @configurationId
                                    AND 
                                    d.IsActive = 1
                                    AND
                                    D.DeliverySubscriptionId = D2.DeliverySubscriptionId FOR XML PATH('')) + '$', ',$', '') 

FROM 
      DeliverySubscription d     
INNER JOIN 
      StatementMacro m ON 
      d.StatementMacroId_fk = m.StatementMacroId    
JOIN 
      DeliverySubscription_Method_Rel dmr ON 
      d.DeliverySubscriptionId = dmr.DeliverySubscriptionId_Fk
JOIN dbo.DeliveryMethod dm ON 
      dmr.DeliveryMethodId_Fk = dm.DeliveryMethodId
WHERE 
      d.DeliveryConfigurationId_fk = @configurationId
      AND 
      d.IsActive = 1

特别是我遇到问题的部分是JOIN DeliverySubscription_Method_Rel，这是一个表示DeliverySubscription和DeliveryMethod之间多对多关系的关系表。

这显示为：

[DeliverySubscription] * ---- * [Delivery Method]

在edmx的数据库图表中。没有创建DeliverySubscription_Method_Rel实体。正如你在SQL语句中看到的那样，JOIN直接在关系表上，但我似乎无法弄清楚如何在LINQ中复制它。请帮忙！

更新：所以环顾网络我发现了一个类似的例子，建议做这样的事情：

from s in Context.DeliverySubscriptions
                from dm in s.DeliveryMethods
                join sm in Context.StatementMacroes on s.StatementMacroId_Fk equals sm.StatementMacroId
                where s.DeliveryConfigurationId_Fk == configurationId
                select new DeliverySubscription_dto
                {
                    DeliverySubscriptionId = s.DeliverySubscriptionId,
                    QubeContactId = s.QubeContactId,
                    statementMacroId_fk = s.StatementMacroId_Fk,
                    MacroName = sm.Name,
                    DeliveryMethod = dm.Name.Replace("$","").Replace(",$","")
                }

...但是因为到目前为止我仍然有很多其他的东西需要改变，所以我无法构建以便测试这个，所以我只想运行这个买你们所有人看看这是否正确

Answer 1

那个查询是一个野兽。如果你没有遇到任何性能问题，我可能只是将它添加到datamodel并使用linq / EF来调用它。

加入与LINQ的多对多关系

1 个答案: