The worst day of an Oracle DBA's career is a restore they've never rehearsed. A datafile is gone, or a

DELETE ran without a WHERE, or a storage array quietly corrupted a handful of blocks — and now the

only thing between you and a résumé-updating outage is a backup you hope works and a procedure you

think you remember.

This is the runbook for that day. It rests on one distinction most people fumble under pressure —