Basic example

For example:

ActiveRecord::Base.transaction do
  david.withdrawal(100)
  mary.deposit(100)
end

This example will only take money from David and give it to Mary if neither withdrawal nor deposit raise an exception. Exceptions will force a ROLLBACK that returns the database to the state before the transaction began. Be aware, though, that the objects will not have their instance data returned to their pre-transactional state.