DistroPropaganda/code/rails41/e1/ar/polymorphic.rb

#---
# Excerpted from "Agile Web Development with Rails",
# published by The Pragmatic Bookshelf.
# Copyrights apply to this code. It may not be used to create training material,
# courses, books, articles, and the like. Contact us if you are in doubt.
# We make no guarantees that this code is fit for any purpose.
# Visit http://www.pragmaticprogrammer.com/titles/rails4 for more book information.
#---
$: << File.dirname(__FILE__)
require "connect"
require "logger"

#ActiveRecord::Base.logger = Logger.new(STDERR)

require "rubygems"
require "active_record"

if ARGV.empty? or ARGV.first == '1'
  ActiveRecord::Schema.define do
  
    create_table :catalog_entries, :force => true do |t|
      t.string :name
      t.datetime :acquired_at
      t.integer :resource_id
      t.string :resource_type
    end
  
    create_table :articles, :force => true do |t|
      t.text :content
    end
  
    create_table :sounds, :force => true do |t|
      t.binary :content
    end
  
    create_table :images, :force => true do |t|
      t.binary :content
    end
  
  end
end

class CatalogEntry < ActiveRecord::Base
  belongs_to :resource, :polymorphic => true
end

class Article < ActiveRecord::Base
  has_one :catalog_entry, :as => :resource
end

class Sound < ActiveRecord::Base
  has_one :catalog_entry, :as => :resource
end

class Image < ActiveRecord::Base
  has_one :catalog_entry, :as => :resource
end

case ARGV.shift
when "1"
  a = Article.new(:content => "This is my new article")
  c = CatalogEntry.new(:name => 'Article One', :acquired_at => Time.now)
  c.resource = a
  c.save!
  article = Article.find(1)
  p article.catalog_entry.name  #=> "Article One"
  
  cat = CatalogEntry.find(1)
  resource = cat.resource 
  p resource                    #=> #<Article:0x640d80 @attributes={"id"=>"1", 
                                #     "content"=>"This is my new article"}>

when "2"
  c = CatalogEntry.new(:name => 'Article One', :acquired_at => Time.now)
  c.resource = Article.new(:content => "This is my new article")
  c.save!

  c = CatalogEntry.new(:name => 'Image One', :acquired_at => Time.now)
  c.resource = Image.new(:content => "some binary data")
  c.save!

  c = CatalogEntry.new(:name => 'Sound One', :acquired_at => Time.now)
  c.resource = Sound.new(:content => "more binary data")
  c.save!

  CatalogEntry.find(:all).each do |c|
    puts "#{c.name}:  #{c.resource.class}"
  end
else
  a = Sound.new(:content => "ding!")
  c = CatalogEntry.new(:name => 'Sound One', :acquired_at => Time.now)
  c.resource = a

  c.save!

  c = CatalogEntry.find 1
  p c.resource

  a = Sound.find :first
  p a.catalog_entry
end