class UserPreference < ActiveRecord::Base self.primary_keys = "user_id", "k" belongs_to :user validates_length_of :k, :within => 1..255 validates_length_of :v, :within => 1..255 # Turn this Node in to an XML Node without the wrapper. def to_xml_node el1 = XML::Node.new "preference" el1["k"] = k el1["v"] = v el1 end end