C# 实体框架使用include和order by生成低效查询

1） 我遇到的第一个问题是，如果执行一个include，然后SQL生成的一个order生成一个内部连接和一个外部连接

var query = from l in Lead.Include("Contact")
orderby l.Contact.FirstName
select l;

在同一个表上生成以下内部联接和外部联接

 INNER JOIN [dbo].[Contact] AS [Extent2] 
      ON [Extent1].[ContactId] = [Extent2].[ContactId]
 LEFT OUTER JOIN [dbo].[Contact] AS [Extent3] 
      ON [Extent1].[ContactId] = [Extent3]. [ContactId]
ORDER BY [Extent2].[FirstName] ASC

这使得查询效率有点低

2） 如果我做多个包含，它总是做第二个作为外部连接

 Lead.Include("OneToOne").Include("OtherOneToOne") <- in this scenario     
                                                      OtherOneToOne is an outer 
                                                     join and OneToOne is an inner 
                                                     join
 Lead.Include("OtherOneToOne").Include("OneToOne") <- in this scenario 
                                                      OneToOne is an outer join 
                                                      and OtherOneToOne is an 
                                                      inner join

---

Lead.Include（“OneToOne”）。Include（“OtherOneToOne”）一个解决方案是让您自己包括：

var query = from l in Lead
select new { l, l.Contact } into row
orderby row.Contact.FirstName
select row;

嗯，事实上，我不认为我设置了正确的使用ctp。。。。。它似乎和RIA玩得不好。。。。让我们看看。。。。