How to recover an Oracle XE Backup
First make sure the database is in archive log mode and running backups on a daily basis. See Oracle XE Backup for instructions on how to do this.
Reverting to a Previous Backup
If something has gone wrong with the database, such as deleting or corrupting a database file, and you want to restore it to the last backup run:
# su – oracle
If the database is in archivelog mode then it will restore from the last backup and a complete recovery of all the archive log files is attempted.