$: << File.dirname(__FILE__) require "connect" require "rubygems" require "active_record" ActiveRecord::Schema.define do # START:migration create_table :counters, :force => true do |t| t.integer :count t.integer :lock_version, :default => 0 end # END:migration end #START:optimistic class Counter < ActiveRecord::Base end Counter.delete_all Counter.create(:count => 0) count1 = Counter.find(:first) count2 = Counter.find(:first) count1.count += 3 count1.save count2.count += 4 count2.save #END:optimistic