destroy_with_lock

# File activerecord/lib/active_record/locking/optimistic.rb, line 113
        def destroy_with_lock #:nodoc:
          return destroy_without_lock unless locking_enabled?

          unless new_record?
            lock_col = self.class.locking_column
            previous_value = send(lock_col).to_i

            affected_rows = connection.delete(
              "DELETE FROM #{self.class.quoted_table_name} " +
              "WHERE #{connection.quote_column_name(self.class.primary_key)} = #{quoted_id} " +
                    "AND #{self.class.quoted_locking_column} = #{quote_value(previous_value)}",
              "#{self.class.name} Destroy"
            )

            unless affected_rows == 1
              raise ActiveRecord::StaleObjectError, "Attempted to delete a stale object: #{self.class.name}"
            end
          end

          freeze
        end