rails method to get the association name of a model

Question

Is there a way to find out what associations a model has? Take these 2 models:

class Comment < ActiveRecord::Base   belongs_to :commentable end  class Post < ActiveRecord::Base   has_many :comments   belongs_to :user end 

I'm looking for something like:

Post.has_many #=> ['comments', ...] Post.belongs_to # => ['user'] Comment.belongs_to # => ['commentable'] 

Answer 1

You're looking for reflect_on_all_associations.

So in short:

Post.reflect_on_all_associations(:has_many) 

...will give an array (of object with attributes like name, etc) of all has_many associations.

Answer 2

The following will list all the associations for a particular instance of Post.

#app/models/post.rb   def list_associations     associations = []     User.reflect_on_all_associations.map(&:name).each do |assoc|       association = send assoc       associations << association if association.present?     end     associations   end