单表继承与embeds_one mogoid

Question

我有一个模特

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

我有另一个继承自评论的类

class RecentComment < Comment
  # certain methods
end

现在,我希望能够创建RecentComment经过post,如果我做Post.last.build_comment(:_type => "RecentComment")了新的注释不会的_type:"RecentComment",同样如果我这样做Post.last.build_recent_comment,它给了我错误说某事像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RecentComment在这种情况下,我不知道如何使用类构建对象.如果有人可以帮助那就是gr8!

注意:我正在使用 gem 'mongoid', '~> 2.0.1'

Answer 1

也许试试吧

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

  embeds_one :recent_comment, :class_name => Comment

并让你的评论类多态

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

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