ruby-on-rails - 带有 embeds_one mogoid 的单表继承

Question

我有一个模型

class Post
  include Mongoid::Document
  include Mongoid::Timestamps

  embeds_one :comment
end

我有评论课

class Comment
  include Mongoid::Document
  include Mongoid::Timestamps

  embedded_in :post

  field :title
  field :description
end

我还有一个从评论继承的类

class RecentComment < Comment
  # certain methods
end

现在我希望能够创建 RecentComment通过 post如果我这样做 Post.last.build_comment(:_type => "RecentComment")新评论不会是 _type:"RecentComment" ，同样如果我这样做 Post.last.build_recent_comment ，它给我错误说某事像 undefined method build_recent_comment for Post class .如果post有 references_many :comments我应该做的Post.last.build_comments({}, RecentComment)没有任何问题。但我不知道如何使用 RecentComment 构建对象在这种情况下类。如果有人能帮忙，那就是gr8!

注意:我正在使用 gem 'mongoid', '~> 2.0.1'

Answer 1

也许试试

class Post
  include Mongoid::Document
  include Mongoid::Timestamps

  embeds_one :recent_comment, :class_name => Comment

并让您的 Comment 类多态

class Comment
  include Mongoid::Document
  include Mongoid::Timestamps

  field :type
  validates_inclusion_of :type, :in => ["recent", "other"]