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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 1.2.1
===========================
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 :products 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 :books, :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