Question

假设我正在创建一个博客网站，用户可以在其中发帖并关注其他用户。我希望用户和用户关注的所有人都有一个ActiveRecord关系。我可以将它作为ruby方法来实现，我在下面的posts_by_me_and_people_i_am_following类中将其称为User。有没有办法用纯粹的ActiveRecord制作它？

class User
    has_many :posts
    has_many :follows
    has_many :followed_users, through: follows, source: :target_user

    has_many :posts_by_followed_users, through: :followed_users, source: :posts

    # I want this to be an ActiveRecord::Relation so that I can filter or order it
    def posts_by_me_and_people_i_am_following
        posts.to_a + posts_by_followed_users.to_a
    end
end

class Post
    belongs_to: :user
end

class Follow
    belongs_to :target_user, class_name: "User"
    belongs_to :source_user, class_name: "User"
end

Answer 1

听起来像是ARel的工作。

def posts_by_me_and_people_i_am_following
  t = Post.arel_table
  results=Post.where(
    t[:user_id].eq(self.id).
    or(t[:user_id].in(self.followed_user_ids))
  )
end

在ActiveRecord中结合使用两个查询

1 个答案: