From: Justin Chan <justin@...>
Date: 2006-10-17T08:53:20+09:00
Subject: Creating enums from ActiveRecord/DB table

Why doesn't the following code work?

require 'rubygems'
require_gem "activerecord"

conf = YAML::load(File.open('database.yml'))
ActiveRecord::Base.establish_connection(conf['test'])

class StuffType < ActiveRecord::Base
has_many :Stuff
end

class Stuff < ActiveRecord::Base
  set_table_name "stuff"
  belongs_to :StuffType
  def initialize
    StuffType.find_all.each do |typ| 
      class_eval %(#{typ.name} = #{typ.id})
    end
  end    
end

StuffType is a DB table with two columns, name, and id.  E.g. 1 = small,
2 = medium, 3 = large.
I want to use it to create an enum for my Stuff class.
Stuff is another DB table with, among other things, a stuff_type_id
column identifying what type it is.

Unfortunately when I plug this code into irb and type something like
Stuff::small, expecting to get 1 returned, I get undefined method
`small' for Stuff:Class.  What am I doing wrong?  Is there a better way
to do what I want?