[英]Rails 4 has_many through
我在Rails 4中有以下代碼:
POST_MODEL_TO_INT = {text_post: 1, video_post: 2}
class Label < ActiveRecord::Base
end
module PostBase
include do
has_many :posts_to_labels, :foreign_key => :post_id, :conditions => { post_model_id: POST_MODEL_TO_INT[self.name.underscore.to_sym] }
has_many :labels, :through => :posts_to_labels
end
end
class TextPost
include PostBase
end
class VideoPost
include PostBase
end
class PostsToLabel < ActiveRecord::Base
belongs_to :post
belongs_to :label
end
TextPost.first.labels => return labels collection
我必須添加什么Label
才能從標簽實例中獲取所有帖子?
Label.first.posts # -> return collection of posts Video, Text ....
Label.first.text_posts # -> return collection of posts Text ....
class Label < ActiveRecord::Base
has_many :posts_to_labels, :conditions => { post_model_id: 2 }
has_many :text_posts, :through => :posts_to_labels
end
class PostsToLabel < ActiveRecord::Base
belongs_to :post
belongs_to :label
belongs_to :text_post, :foreign_key => :post_id
end
我找到單一資源的解決方案,但不明白為什么我需要在hassmany中添加PostsToLabel嗎?
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.