gistfile1.rb

# This is the current solution. It merely validates the string's inclusion in
# the given list, and saves it as a string.

ActiveRecord::Schema.define(:version => 20110101000000) do
  create_table "foos", :force => true do |t|
    t.string "bar"
  end
end

class Foo < ActiveRecord::Base
  validates_inclusion_of :bar, :in => ["a", "b", "c"]
end

# It might be helpful to add a list of the available values for the bar attribute

class Foo < ActiveRecord::Base
  validates_inclusion_of :bar, :in => self.class.bars

  class << self
    def bars
      ["a","b","c"]
    end
  end
end

# Or I could reuse a solution I saw on the client model in xrono, storing the
# value as an integer in the db, and defining custom getters and setters

ActiveRecord::Schema.define(:version => 20110101000000) do
  create_table "foos", :force => true do |t|
    t.integer "bar"
  end
end

class Foo < ActiveRecord::Base
  validates_inclusion_of :bar, :in => self.class.bars.keys

  def bar
    self.class.bars[attributes[:bar]]
  end

  def bar=(value)
    write_attribute(:bar, self.class.bars[value])
  end

  class << self
    def bars
      {
        "a" => 1,
        "b" => 2,
        "c" => 3
      }
    end
  end
end