CITIER

What is it?

CITIER (Class Inheritance & Table Inheritance Embeddings for Rails) is a very simple way of implementing Multiple Table inheritance in Rails.

In short it allows you (finally) to do this:

class Product < ActiveRecord::Base
  acts_as_citier
  validates_presence_of :name
  def an_awesome_product
    puts "I #{name} am an awesome product"
  end
end

class Book < Product
  acts_as_citier
  validates_presence_of :title
  
  def an_awesome_book
    self.an_awesome_product
    puts "A book to be precise"
  end
end

class Dictionary < Book
  acts_as_citier
  validates_presence_of :language
  
  def is_awesome
    self.an_awesome_book
    puts "I am a dictionary. Yeah!"
  end
end

There are two lines you need to add to your migration files as well, see Here for full information

$ rails console
Loading development environment (Rails 3.0.7)
>> :001 > d = Dictionary.new(:name=>nil,:price=>25.99,:title=>nil,:language=>nil)
citier -> Root Class
citier -> table_name -> products
citier -> Non Root Class
citier -> table_name -> books
citier -> tablename (view) -> view_books
citier -> Non Root Class
citier -> table_name -> dictionaries
citier -> tablename (view) -> view_dictionaries
 => #<Dictionary id: nil, type: "Dictionary", name: nil, price: 25, created_at: nil, updated_at: nil, title: nil, author: nil, language: nil> 
>> :002 > d.valid?
 => false 
>> :003 > d.errors
 => #<OrderedHash {:language=>["can't be blank"], :name=>["can't be blank"], :title=>["can't be blank"]}> 
>> :004 > d = Dictionary.new(:name=>"Ox. Eng. Dict",:price=>25.99,:title=>"The Oxford English Dictionary",:language=>"English")
 => #<Dictionary id: nil, type: "Dictionary", name: "Ox. Eng. Dict", price: 25, created_at: nil, updated_at: nil, title: "The Oxford English Dictionary", author: nil, language: "English"> 
>> :005 > d.valid?
 => true
>> :006 > d.is_awesome()
I Ox. Eng. Dict am an awesome product
A book to be precise
I am a dictionary. Yeah!
=> nil
>> :007 > d.save()
citier -> Non-Root Class Dictionary
citier -> Non-Root Class Book
citier -> UPDATE products SET type = 'Product' WHERE id = 1
citier -> SQL : UPDATE products SET type = 'Book' WHERE id = 1
citier -> SQL : UPDATE products SET type = 'Dictionary' WHERE id = 1
 => true 
>> :008 > Dictionary.all()
 => [#<Dictionary id: 1, type: "Dictionary", name: "Ox. Eng. Dict", price: 25, created_at: "2011-04-28 22:46:23", updated_at: "2011-04-28 22:46:23", title: "The Oxford English Dictionary", author: nil, language: "English">] 
>> :009 > Product.all()
 => [#<Dictionary id: 1, type: "Dictionary", name: "Ox. Eng. Dict", price: 25, created_at: "2011-04-28 22:46:23", updated_at: "2011-04-28 22:46:23", title: "The Oxford English Dictionary", author: nil, language: "English">] 
>> :010 > d = Dictionary.all().first()
 => #<Dictionary id: 1, type: "Dictionary", name: "Ox. Eng. Dict", price: 25, created_at: "2011-04-28 22:46:23", updated_at: "2011-04-28 22:46:23", title: "The Oxford English Dictionary", author: nil, language: "English"> 
>> :011 > d.delete()
citier -> Deleting Dictionary with ID 1
citier -> Deleting back up hierarchy Dictionary
citier -> Deleting back up hierarchy Book
 => true 
>> :012 > Dictionary.all()
 => []

Cool huh?

It is based on original code by ALTRABio (www.github.com/altrabio/)

For full information please go to the github page: http://peterhamilton.github.com/citier/

Contributing to citier

• Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet.
• Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it.
• Fork the project.
• Start a feature/bugfix branch.
• Commit and push until you are happy with your contribution.
• Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
• Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.

Copyright

Copyright (c) 2012 Peter Hamilton. See LICENSE.txt for further details.