Question

So I’m teaching myself Ruby on Rails, with a PHP background. I’ve written a sloppy, proof-of-concept PHP application called ‘2NDP.‘ I want to re-create this in Ruby on Rails (but more basic, more clean, and with a better interface), so I can learn some of the basics.

2NDP is a website where you can basically write your own ‘Choose-Your-Own-Adventure’ books, but collaboratively, with other people. The way I made this work with PHP/MySQL is, I had a table of stories and a table of pages. The pages would belong to stories (obviously), but each page would have references to up to four other pages by having four separate columns, one for each possible page ID that could be referenced.

So right now in my RoR application, I have ‘stories’ that have ‘pages’ that are associated with them. I need a way to get the pages to reference each other, but the possibility of more than one reference per page (one page may reference up to four other pages).

I really like the ‘references’ thing that RoR has, but is there any way to gracefully implement this sort of system? Keep in mind that my only RoR experience is walking through four tutorials, and I’m trying to re-apply what I’ve learned with a ‘real-life application.’

Answer 1

Rather then having four seperate columns, a separate joining table might be more appropriate. For example:

Pages -> LinkedPages -> Pages

Then you can create a has_many through relationship.

class Pages < ActiveRecord::Base   has_many :linked_pages   has_many :pages, :through => :linked_pages end  class LinkedPages < ActiveRecord::Base   belongs_to :pages, :class_name => 'Pages', :foreign_key => 'page_id'   belongs_to :linked_pages, :class_name => 'Pages', :foreign_key => 'linked_id'  end 

Then when using your Page object you can simply say:

my_page.pages