how (replace|create) an enum field on rails 2.0 migrations?

Question

I would like to create an enum field at sone migration I\'m doing, I tried searching in google but I can\'t find the way to do it in the migration

the only thing I f

Answer 1

I have dozens of these little enums, with 3-300 entries in each. I implement them as lookup tables. I don't have a model file for each one; I use some metaprogramming to generate a model for each, since each table has the same set of columns (id, name, description).

Since some of the sets had enough elements to warrant their own table, it was more consistent to move them all to tables. Just another option if you'll have more of these enums later.

EDIT: Here's how I generate the models:

ACTIVE_RECORD_ENUMS = %w{
  AccountState
  ClientType
  Country
  # ...
}

ACTIVE_RECORD_ENUMS.each do |klass|
  eval "class #{klass} < ActiveRecord::Base; end"
  klass.constantize.class_eval do
    class << self

      def id_for(name)
        ids[name.to_s.strip.humanize.downcase]
      end

      def value_for(id)
        values[id.to_i]
      end

      def values
        @values ||= find(:all).inject({}) {|h,m| h[m.send(primary_key)] = m.name; h}
      end

      def ids
        @ids ||= self.values.inject({}) {|h, {k, v}| h[v.downcase] = k; h}
      end

    end
  end
end

This file lives in the models directory, and is included in application_config.rb. This lets me do stuff like this:

AccountState.ids 
# => {"active" => 1, "deleted" => 2}
AccountState.values 
# => {1 => "Active", 2 => "Deleted"}
AccountState.id_for("Active") 
# => 1
AccountState.value_for(1) 
# => "active"

Answer 2

Another option: drop to SQL.

def self.up
  execute "ALTER TABLE `payments` ADD `status` ENUM('accepted', 'cancelled', 'pending')"
end

Answer 3

With simple_form i use this:

<%= f.input :gender, :collection => {'Male' => 'male','Female' => 'female'}, :include_blank => false %>

Answer 4

You can try the (very) comprehensive jeff's enumerated_attribute gem OR go with this simple workaround:

class Person < ActiveRecord::Base
  SEX = [:male, :female]

  def sex
    SEX[read_attribute(:sex)]
  end

  def sex=(value)
    write_attribute(:sex, SEX.index(value))
  end
end

And then declare the sex attribute as an integer:

t.integer :sex

This worked very fine for me! =D

Answer 5

Have you looked at the enum-column plugin on RubyForge?

Answer 6

Look at tip #3 on http://zargony.com/2008/04/28/five-tips-for-developing-rails-applications

This exactly what you need!

 class User < ActiveRecord::Base
   validates_inclusion_of :status, :in => [:active, :inactive]

   def status
     read_attribute(:status).to_sym
   end

   def status= (value)
     write_attribute(:status, value.to_s)
   end
 end

HTH