class MigrateReservationToStatisticProfile < ActiveRecord::Migration def up Reservation.all.each do |r| user = User.find(r.user_id) r.update_column( 'statistic_profile_id', user.statistic_profile.id ) end end def down Reservation.all.each do |r| statistic_profile = User.find(r.statistic_profile_id) r.update_column( 'user_id', statistic_profile.user_id ) end end end