Parent association for embedded document using MongoMapper

Question

If I have:

class Post
  include MongoMapper::Document

  has_many :comments
end

If I do:

class Comment
  include MongoMapper::EmbeddedDocument

  belongs_to :post # relevant part
end

Does that create an association using _root_document/_parent_document, or do I have to add the (redundant) key :post_id?

Answer 1

You do not need post_id or belongs_to :post. Instead, you can use embedded_in :post. This will make a read method for _parent_reference named post so you can say comment.post instead of comment._parent_reference.

class Comment
  include MongoMapper::EmbeddedDocument

  embedded_in :post
end