validates_presence_of :id
validates_length_of :k, :v, :maximum => 255, :allow_blank => true
validates_uniqueness_of :id, :scope => [:k, :version]
validates_presence_of :id
validates_length_of :k, :v, :maximum => 255, :allow_blank => true
validates_uniqueness_of :id, :scope => [:k, :version]