How do I check if an association exists in ActiveRecord from inside a model?

Question

I tried all combinations that I could find online and it always fails.

class Profile < ActiveRecord::Base

  belongs_to  :user, :dependent => :destroy
  has_one     :match # educational matches 

  accepts_nested_attributes_for :match
  attr_accessor                 :form

  unless match.present?
    searchable do

      integer :id
      string :country
      string :state
    end
  end
end

and

Match belongs_to :profile

Inside the Profile model I try to do:

  unless profile.match.exist? (does profile have a match association existing?) 
    .. do something

  end

You can't do `unless match.present?` at the class level, since you're using no special Profile instance, here. It's not the Profile class that has one match, it's profile instances. — kik, Oct 19 '13 at 16:19
@OlivierElMekki so any way how to do it then using a lambda perhaps? — Rubytastic, Oct 20 '13 at 21:04
I don't use sunspot myself, but it seems it can handle conditional indexing passing proc [as :if option](http://mikepackdev.com/blog_posts/19-conditional-indexing-with-sunspot). — kik, Oct 21 '13 at 00:35

score 2 · Accepted Answer · answered Oct 26 '13 at 15:49

2

Inspired by the blog post that Olivier linked to and confirmed in the Sunspot documentation, you could do:

# In your Profile model
searchable :if => proc { |profile| profile.match.present? } do
  integer :id
  string :country
  string :state
end

answered Oct 26 '13 at 15:49

carols10cents

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How do I check if an association exists in ActiveRecord from inside a model?

1 Answers1