Question

我有一个User模型

class User < ApplicationRecord
  has_many :posts, dependent: :destroy
  has_many :collections, dependent: :destroy

  # here, I want to get :collected_posts (all posts that all user collections have)
  # has_many :collected_posts, through: :collections, source: :post (this throws error)
end

这是我的Post模型

class Post < ApplicationRecord
  belongs_to :user
  has_many :post_collections, dependent: :destroy
end

这是我的Collection模型

class Collection < ApplicationRecord
  belongs_to :user
  has_many :post_collections, dependent: :destroy
  has_many :posts, through: :post_collections
end

这是我的PostCollection模型

class PostCollection < ApplicationRecord
  belongs_to :post
  belongs_to :collection
end

我想current_user.collected_posts来获取他保存在所有收藏集中的所有帖子。

但是，我收到此错误

# ActiveRecord::HasManyThroughSourceAssociationNotFoundError (Could not find the source association(s) :post in model Collection. Try 'has_many :collected_posts, :through => :collections, :source => <name>'. Is it one of user, post_collections, or posts?)

因为集合对象中没有post_id。

如何获取所有用户收藏集的所有帖子？谢谢！

Answer 1

将此添加到User类

has_many :collected_posts, through: :collections, source: :posts

Answer 2

我会在用户模型中这样做

 def collected_posts
   self.collections.map(&:posts).flatten
 end

用户拥有收藏集，收藏集拥有帖子（通过帖子收藏集），map函数将在每个收藏集对象上调用该函数并返回帖子。

ActiveRecord :: HasManyThroughAssociationNotFoundError

2 个答案: