的has_many：通过与：foreign_key

Question

我的模式是这样的：

class Post < ActiveRecord::Base 
    has_many :aspect_visibilities, :as => :shareable, :primary_key => :guid, :foreign_key => :shareable_guid 
    has_many :aspects, :through => :aspect_visibilities 
end 

class AspectVisibility < ActiveRecord::Base 
    belongs_to :aspect 
    validates_presence_of :aspect 

    belongs_to :shareable, :polymorphic => true, :primary_key => :guid, :foreign_key => :shareable_guid 
    validates_presence_of :shareable 
end 

class Aspect < ActiveRecord::Base 
    has_many :aspect_visibilities 
    has_many :posts, :through => :aspect_visibilities, :source => :shareable, :source_type => 'Post' 
end 

我的问题是，当我插入后成看点帖子的ID插入AspectVisibility作为邮政的关键。但实际上应该插入邮政的指导。

我见过的解决方案是这样的：

class Post < ActiveRecord::Base 
    set_primary_key :guid 
    [...] 
end 

但我并不想改变文章的外键一般，但只是为AspectVisibility关联。

有谁能告诉我该怎么做？

谢谢！

Answer 1

我尝试了同样的事情，并且这篇文章的guid是通过shareable_guid插入到aspect visibility中的。这就是我正在做的。

>aspect = Aspect.create(:name => "name") 
>#<Aspect id: 1, name: "name", created_at: "2011-11-24 18:08:53", updated_at: "2011-11- 24 18:08:53"> 
> post = Post.create(:guid => 'guid', :name => "name") 
>#<Post id: 1, guid: "guid", name: "name", created_at: "2011-11-24 18:09:26", updated_at: "2011-11-24 18:09:26"> 
> aspect.posts << post 
>[#<Post id: 1, guid: "guid", name: "name", created_at: "2011-11-24 18:09:26", updated_at: "2011-11-24 18:09:26">] 
>aspect.aspect_visibilities 
>[#<AspectVisibility id: 1, guid: nil, shareable_type: "Post", **shareable_guid: "guid"**, aspect_id: 1, created_at: "2011-11-24 18:09:48", updated_at: "2011-11-24 18:09:48">] 

请注意aspect_visibility中shareable_guid的值。它被设置为引导而不是id。