categorizations end class Categorization < ActiveRecord::Base belongs_to :post belongs_to :category end class Post < ActiveRecord::Base has_many :categorizations has_many :categories, :through => categorizations end Monday, February 27, 12 Allows for validations, along with attaching data to the association. How about Users with Ratings & Songs?
ActiveRecord::Base has_and_belongs_to_many :posts end Monday, February 27, 12 No touching the table, just a link. Still need to write migration though!