The data file belonging to the SYSTEM tablespace is corrupted and no backup of the file is available.
How do you recover the data file?
The data file cannot be recovered.
The date file can be restored from the SYSTEM auto backup.
Take the tablespace offline, drop, and re-create it.
Recovery Manager (RMAN) is used to recover the data file.
The ALTER DATABSE CREATE DATAFILE.. command is used to recover the data file.
The tablespace that contains the Oracle data dictionary for a database, which is the metadata that describes the complete contnents of the database. The SYSTEM tablespace is unlike other tablespaces in that all datafiles contained in the tablespace must be online for Oracle to function. If a media failure affects one of the datafiles in SYSTEM, then you must mount the database and recover. The question ask to “How to recover?”, but also says that there is NO BACKUP AVAILABLE.
To restore a datafile or control file from backup is to retrieve the file onto disk from a backup location on tape, disk or other media, and make it available to the database server. To recover a datafile (also called performing recovery on a datafile), is to take a restored copy of the datafile and apply to it changes recorded in the database’s redo logs. To recover a whole database is to perform recovery on each of its datafiles.
REF.: Oracle(r) 10g Backup and Recovery Guide 1-5