rails method to get the association name of a model

user_156746 0
Viewed 21537

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']
rails-activerecord ruby-on-rails
2 Answers

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.

thenduks_2100

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
user_12993620
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