_lock_value_for_database

# File activerecord/lib/active_record/locking/optimistic.rb, line 134
        def _lock_value_for_database(locking_column)
          if will_save_change_to_attribute?(locking_column)
            @attributes[locking_column].value_for_database
          else
            @attributes[locking_column].original_value_for_database
          end
        end