The REQUEST_HANDLE SCOPE clause is only used by RDBPRE and RDML
    programs, not with RDO or RDB$INTERPRET. In a program where an
    RDO request occurs within a higher level language loop, the
    REQUEST_HANDLE SCOPE clause determines whether system or user
    request handles are set to zero in the RDO FINISH statement
    within the loop.

    With the REQUEST_HANDLE SCOPE is FINISH clause, the values of the
    request handles are set to zero after the RDO statement FINISH
    executes.