ActiveRecord Optimistic Locking

optimistic.rb

require 'active_record'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :orders do |t|
    t.integer :total
    t.string :lock_version
  end
end

class Order < ActiveRecord::Base ; end

Order.create

object_1 = Order.find(1)
object_2 = Order.find(1)

object_1.total = 100
object_1.save # Succeeds!

object_2.total = 200
object_2.save # Raises ActiveRecord::StaleObjectError