你如何使用mongo mapper制作belongs

你如何使用mongo mapper制作belongs_to？(How do you make a belongs_to required with mongo mapper?)

我正在使用Mongo Mapper ，我正在试图弄清楚你是如何制作一份文件的。 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，并没有强制说答案有一个问题：

> Answer.new.save => true

I am using Mongo Mapper and I'm trying to figure out how you make a document required. For example, I want to do something like this:

class Question include MongoMapper::Document many :answers end class Answer include MongoMapper::Document belongs_to :question, :required => true end

But when I do, it's doesn't enforce that the answer have a question:

> Answer.new.save => true

最满意答案

MongoMapper包含ActiveModel :: Validations，因此您可以像活动记录一样使用验证。 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 docs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

MongoMapper includes ActiveModel::Validations so you can use validations just like active record. The following should work:

class Question include MongoMapper::Document many :answers end class Answer include MongoMapper::Document belongs_to :question validates :question, :presence => true end

You can check the rails docs for more info on those validations here: http://api.rubyonrails.org/classes/ActiveModel/Validations/ClassMethods.html#method-i-validates