EF：交叉edmx（相同的数据库）linq-to-entites查询 [英] EF: Cross edmx (same DB) linq-to-entites query

问题描述

如何在单独的程序集中使用两个EDMX，而不是在同一个数据库中，
创建一个使用它们的LINQ到实体的查询？

例如

这是我要做的：

 $（$）
 {
 var items2 = context2.Items .Where（item2 => item2.Color ==Red）; 
 
 var query = context1.Items.Where（item => 
 items2.Any（item2 => item2.PainterId == item.PainterId））; 
} 
} 
  

 >这将导致NotSupportedException。 >
  消息：指定的LINQ表达式包含对与不同上下文相关联的查询的引用。

 >即使替换了Entities2，此异常也是抛出与实体1

   （即使两个上下文都是相同的EDMX），并且都使用相同的连接字符串。

---

比较，另一方面工作和结果在一个单一的SQL语句：

  using（var context1 = new Entities1（）） 
 {
 var items2 = context2.Items.Where（item2 => item2.Color ==Red）; 
 
 var query = context1.Items.Where（item => 
 items2.Any（item2 => item2.PainterId == item.PainterId））; 
} 
  

限制条件：

我的意图是使用两个EDMX设计器支持 - 不要以破坏设计器的方式攻击EDMX，或者从数据库更新时被覆盖。 / p>

EDMX＃1无法知道EDMX＃2（但＃2可以知道＃1）。

我希望结果转换为单个SQL查询，而不是从第一部分到内存中读取结果，然后将其作为第二部分查询的输入返回到数据库。

---

相关，但不是我要找的：

• Linq to Entities / Entity Framework交叉edmxjoin ;


• 同一个.net解决方案中的多个edmx

解决方案

你以你的问题的方式限制了你的要求：不可能。最好的唯一推荐的解决方案是在第二个链接中引用ADO.NET团队博客关于使用大型模型的文章。

我写了关于一个黑客（并且我成功地在一个项目中使用），但是它还有一个缺点 - 您必须对两个EDMX使用单个上下文。即使这样做，我也不建议使用这种方式，因为它可能会有未开发的缺点，因为它内部省略了EF中许多其他地方使用的容器名称。

How can I use two EDMXs, in separate assemblies, yet above the SAME database,
to create a linq-to-entities query that uses them both?

E.g.

This is what I am trying to do:

using (var context1 = new Entities1())
{
    using (var context2 = new Entities2())
    {
        var items2 = context2.Items.Where(item2 => item2.Color == "Red");

        var query = context1.Items.Where(item =>
            items2.Any(item2 => item2.PainterId == item.PainterId));
    }
}

 > This results in NotSupportedException.
   Message: "The specified LINQ expression contains references to queries that are associated with different contexts."

 > This exception is throw even if Entities2 is replaced with Entities1
   (even if both contexts are from same EDMX) and both using the same connection string.

---

For comparison, this on the other hand works and results in a single SQL statement:

using (var context1 = new Entities1())
{
    var items2 = context2.Items.Where(item2 => item2.Color == "Red");

    var query = context1.Items.Where(item =>
        items2.Any(item2 => item2.PainterId == item.PainterId));
}

Constraints:

My intent is to use two EDMXs WITH designer support - no hacking EDMX in a way that breaks designer or that gets overwritten when updating from database.

EDMX #1 can not know about EDMX #2 (however #2 can know about #1).

I want the result to translate to a single SQL query, not to read results from first part to memory, then return them to database as an input for second part of query.

---

Related, but not what I am looking for:

• Cross database joins in Entity Framework4
  
• Linq to Entities / Entity Framework cross edmx "join"
  
• multiple edmx in the same .net solution
  

解决方案

You constrained your requirements in the way that answers your question: No it is not possible. The best and only recommended solution is in the second link which references ADO.NET team blog's article about working with large models.

I wrote about a hack (and I successfully used in one project) which works as well but it has another disadvantage - you must use single context for both EDMXs. Even it worked I don't recommend using that way because it can have unexplored disadvantages because it internally omits container name which is used in many other places in EF.

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