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Part 1 / 3 : Sample Forum

Keat | url
on Mon Sep 13 20:32:00 SGT 2004

This is a sample forum written as a quick intro to Ruby and Rails.

The only table used is:

CREATE TABLE posts (
  id int(19) NOT NULL auto_increment,
  subject varchar(255) NOT NULL default '',
  message text NOT NULL,
  author varchar(255) NOT NULL default '',
  email varchar(255) default NULL,
  url varchar(255) default NULL,
  created_at datetime default NULL,
  post_id int(19) default NULL,
  type varchar(255) default NULL,
  PRIMARY KEY  (id)
)

Using ActiveRecord class in Rails, id, post_id and type columns of the table is dealt with automatically. The main model (in MVC) here is Post. And in rails, you do this (the 'def before_destroy' chunk is quite optional)

require 'active_record'
require 'forum_controller'

class Post < ActiveRecord::Base
  def before_destroy
    sqlId = ForumController.quote(id)
    Comment.find_all("post_id = #{sqlId}").each do |entry|
      entry.destroy
    end
  end
end

In our forum, we'll have comments on the topics posted. Declaring this model is even easier:

require 'post'

class Comment < Post
  belongs_to :post
  # it is assumed the foreign_key => "post_id"
  # however, manually assigning a foreign key
  # will work also too.
end

Comments (2)

Keith, yes, there is. As long as we're talking about the id field of an object, you don't have to name it explicitly to find().
| url
on Mon Sep 20 18:46:00 SGT 2004 [Delete]

I'm not learned enough about Ruby or Rails .. but hopefully there is actually a framework/method to do

Comment.find_all("post_id = #{sqlId}").each ...

without exposing the column name.
Keat
on Mon Sep 13 21:21:00 SGT 2004 [Delete]

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