Versions ======== If you are using Rails 2.3.8 or other version < 3, you have to use the version 1.1.x of this plugin, for Rails 3 you need to use the version 1.2.x or master of this plugin. ClassTableInheritance 1.2.0 =========================== This is an ActiveRecord plugin designed to allow simple multiple table (class) inheritance. This plugin was inspired by: inherits_from plugin => http://github.com/rwl4/inherits_from and Multiple Table Inheritance with ActiveRecord => http://mediumexposure.com/multiple-table-inheritance-active-record/ How to install ============== gem install class-table-inheritance Example ======= # Migrations create_table :product do |t| t.string :description, :null => false t.string :subtype # Only if you need access of both side see example t.decimal :price t.timestamps end create_table :book, :inherits => :product do |t| t.string :author, :null => false end create_table :videos, :inherits => :product do |t| t.string :year, :null => false t.string :genre, :null => false end # Models class Product < ActiveRecord::Base acts_as_superclass # only if you want top-down access. end class Book < ActiveRecord::Base inherits_from :product end class Video < ActiveRecord::Base inherits_from :product end book = Book.find(1) book.name => "Agile Development with Rails" book.author => "Dave Thomas" book.price => 19.00 video = Video.find(2) video.name => "Inseption" video.year => "2010" video.genre => "SCI-FI" video.price => 22.00 book = Book.new book.name = "Hamlet" book.author = "Shakespeare, William" book.price => 14.00 book.save Top-down access (Polymorphic) ============================= if you want to access product and get field in the subclass do you need to create a field subtype:string in superclass and ad acts_as_superclass in superclass and now you can do like this. product = Product.find 1 # This is a Book instance. product.author product = Product.find 2 # This is a Video instance. product.genre if you need help contanct me: bfscordeiro (at) gmail.com . Copyright (c) 2010 Bruno Cordeiro, released under the MIT license