Question

I would like to find the assocations of an ActiveRecord class at runtime…

Let’s assume I have the following:

class Person < ActiveRecord::Base   has_many :chairs   has_many :pens end  class Chair < ActiveRecord::Base   belongs_to :person end  class Pen < ActiveRecord::Base   belongs_to :person end 

How can I find out at runtime that Person ‘has many’ Chairs and Pens, and vice versa? I’m looking for a method that would return an array of strings (if such a method exists). i.e.

Person.has_many_assocations  

would return:

['chairs', 'pens']  

and

Pen.belongs_to_associations 

would return:

['person'] 

Am I missing a method like this that exists??

Thanks for your help.

Answer 1

I think the ActiveRecord::Reflection class may be what you’re looking for. From the documentation:

  Account.reflect_on_all_associations             # returns an array of all associations   Account.reflect_on_all_associations(:has_many)  # returns an array of all has_many associations