ruby - 你如何使 belongs_to 成为 mongo 映射器所必需的？

Question

我正在使用 Mongo Mapper我想弄清楚你是如何要求提供文件的。例如，我想做这样的事情:

class Question
  include MongoMapper::Document

  many :answers
end

class Answer
  include MongoMapper::Document

  belongs_to :question, :required => true
end

但是当我这样做时，并不强制要求答案有问题:

> Answer.new.save
 => true

Answer 1

MongoMapper 包含 ActiveModel::Validations，因此您可以像使用事件记录一样使用验证。以下应该有效:

class Question
  include MongoMapper::Document

  many :answers
end

class Answer
  include MongoMapper::Document

  belongs_to :question

  validates :question, :presence => true
end

您可以在此处查看 Rails 文档以获取有关这些验证的更多信息:http://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validates