CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-3ruby-on-rails-3.2mongoid
hyperrjas
hyperrjas

Reputation: 10744

check if relation exists has_one mongoid

class Question
  include Mongoid::Document
  include Mongoid::Timestamps

  field :title, :type => String

  has_one :response
end

class Response
  include Mongoid::Document
  include Mongoid::Timestamps

  field :content, :type => String

  belongs_to :question

end

console:

1.9.3p448 :014 > Question.where(:response => nil).size
 => 3 
1.9.3p448 :016 > Question.where(:response.ne => nil).size
 => 0

However all questions has one response created and associated!

Thanks!

Upvotes: 1

Views: 1085

Answers (1)

Bart
Bart

Reputation: 2656

The ID field is stored in the child object only, therefore Question has no knowledge of its Response (no response_id field).

You can achieve the goal like this:

Response.ne(question_id: nil).map(&:question)

Or, to fetch questions without responses:

Question.not.in(id: Response.pluck(:question_id))

Upvotes: 4

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