TRANSACTION_HANDLE     The TRANSACTION_HANDLE keyword followed by
    var                    a host language variable. A transaction
                           handle identifies a transaction. If
                           you do not supply a transaction handle
                           explicitly, RDML uses the default
                           transaction handle.

    on-error               The ON ERROR clause. Specifies host
                           language statement(s) to be performed
                           if an error occurs during the ROLLBACK
                           operation. For more information see the
                           entry on ON ERROR.