From: zdennis <zdennis@...>
Date: 2006-10-18T07:19:01+09:00
Subject: Re: Creating enums from ActiveRecord/DB table

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Justin Chan wrote:
> 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

When you create a new Stuff record you aren't guaranteed it has an id, ie, has it been saved to the database or not? Also,
ActiveRecord doesn't create new records (when finding records from the database) using the "new" method, so "initialize" never
gets it.

When do you want your "enum" like behavior to be created, after creation, after update, after find, when the class lods?

Also, do you want the relationship to StuffType to be an the instance level or at the class.

ie, do you want to say:
  stuff = Stuff.find( 1 )
  stuff.small # assume small is one of your fields in stuff_types

or do you want to say:
  Stuff.small #assume small is one of your fields in stuff_types

Zach
http://blogs.mktec.com/zdennis
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