class Ship < ActiveRecord::Base self.record_timestamps = false belongs_to :pirate belongs_to :update_only_pirate, :class_name => 'Pirate' has_many :parts, :class_name => 'ShipPart' accepts_nested_attributes_for :parts, :allow_destroy => true accepts_nested_attributes_for :pirate, :allow_destroy => true, :reject_if => proc { |attributes| attributes.empty? } accepts_nested_attributes_for :update_only_pirate, :update_only => true validates_presence_of :name attr_accessor :cancel_save_from_callback before_save :cancel_save_callback_method, :if => :cancel_save_from_callback def cancel_save_callback_method false end end