rails/activerecord/test/models/reference.rb

class Reference < ActiveRecord::Base
  belongs_to :person
  belongs_to :job

  class << self
    attr_accessor :make_comments
  end

  before_destroy :make_comments

  def make_comments
    if self.class.make_comments
      person.update_attributes :comments => "Reference destroyed"
    end
  end
end

class BadReference < ActiveRecord::Base
  self.table_name ='references'
  default_scope :conditions => {:favourite => false }
end