thanks slimdave, meaning set autocommit on can be used for batch data loading where rollback segment/undo tbs will be used only for single transaction(cause it commit just after every single DML ). is that correct?
I suppose so, but personally i never use it. I prefer issuing commits explicitly, as I think it aids supportability, and there's too many cases where i want multiple statements to commit or rollback together.
With External Tables available in 9i, I don't have a lot of use for SQL*Plus-based scripts -- I tend do do them in PL/SQL and schedule with DBMS_JOB.