在主动记录中深度嵌套连接(deeply nested joins in activerecord)

 我试图在我的网站中优化我的查询。 
 
 我有3个模型，照片，人物，外观 
 
 照片has_many外观，许多人通过外观外观表只有一个person_id，photo_id 
 
 现在，如果我要对“人物”进行搜索，并且想要加载他们的外观和照片，我会这样做： 
 
 Person.joins(:appearances => :photo).limit(5)
 
 现在，我不确定这是否理想，但假设我的人有属于照片的外观，而照片又有外表和其他人。 我甚至不知道在香草SQL中是否或如何做到这一点，但我只是好奇，如果这是可能的。 
 
  Person.joins(:appearances => :photo => :appearaces => :person).limit(5)
 
 这个语法导致了错误，我只是好奇，我正在处理在视图中获取照片的外观和人物，我只是想试验加载时间，看看这是否可能。 

I'm trying to optimize my queries throughout my site. 
 
I have 3 models, Photo, Person, Appearances
 
Photo has_many appearances, and many people through appearances Appearances table just has a person_id, photo_id
 
Now, if I were to do a search on a 'Person' and I wanted to eager load their appearances and photos, I would do something like this: 
 
 Person.joins(:appearances => :photo).limit(5)
 
Now, I'm not sure if this is ideal, but hypothetically my person has appearances which belongs to a photo, which in turn has appearances and other people. I don't even know if or how you'd do this in vanilla SQL, but I am just curious if this is possible. 
 
  Person.joins(:appearances => :photo => :appearaces => :person).limit(5)
 
This syntax results in errors, again, I'm just curious, I'm handling getting the appearances and people of a photo inside my views, I just wanted to experiment with load times and see if this was even possible. 

原文：https://stackoverflow.com/questions/13404843