Demonstrates the use of virtual attributes to create form fields that do not map directly to the database

birthday.rb

class Birthday < ActiveRecord::Base
  attr_accessible :date, :name, :day, :month, :year
  before_validation :make_date
	
  def day
    (date.nil?)? @day : date.split("-")[0]
  end

  def month
   (date.nil?)? @month : date.split("-")[1]
  end

  def year
    (date.nil?)? @year : date.split("-")[2]
  end

  def day=(val)
    @day = val
  end

  def month=(val)
    @month = val
  end

  def year=(val)
    @year = val
  end
	
  def make_date
    birthday = [@day, @month, @year].join("-")
    self.date = (birthday == "--")? "" : birthday
  end
end