class PCustomerRib < ActiveRecord::Base belongs_to :p_customer has_many :p_documents, :dependent => :nullify def generate_rum if self.sign_date self.rum = "JOA"+self.p_customer.ref.to_s+self.sign_date.year.to_s+('%02d' % self.sign_date.month)+('%02d' % self.sign_date.day) self.save end end end