Answers to Review Questions - OCP: Oracle Database 12c Administrator Certified Professional - page 665

6. C. If the database has not shut down yet, you have an opportunity to preserve your
data changes. Issue a checkpoint, which will flush dirty buffers to disk. Then shut
down the database normally, if possible ( SHUTDOWN , SHUTDOWN IMMEDIATE ). You then
should mount the database with the STARTUP MOUNT command followed by clearing
and rebuilding the log file with the ALTER DATABASE CLEAR LOGFILE command. Finally,
attempt to open the database with the ALTER DATABASE OPEN command.
7. A, B, C, D. Change-based recovery allows you to recover the database to a specific SCN.
Cancel-based recovery provides the ability to cancel recovery after each archived redo log
application. Time-based recovery provides the ability to recover the database up to a spe-
cific point in time. Sequence number-based recovery allows you to recover the database
up to a specific log sequence number.
8. A, C, D. To perform a full recovery of the database in ARCHIVELOG mode, you
would need the database data files, the archived redo logs, and a backup control file.
9. E. NOARCHIVELOG mode does not support any kind of point-in-time recovery of
the Oracle Database.
10. C. You should first start the database in mount mode using the STARTUP MOUNT com-
mand. You then issue the ALTER DATABASE CLEAR UNARCHIVED LOGFILE command.
This will clear the log file if it needs to be archived and recreate the online redo log
group. If that command is successful, then you issue the ALTER DATABASE OPEN com-
mand. The last step, backing up the database, is very important since your previous
backup will not be able to recover the database beyond the point of the cleared redo log
sequence number. This is because you have skipped a redo log in the redo log stream.
11. A. You would first take the missing data file offline with the ALTER DATABASE DATAFILE
4 OFFLINE command. You should then restore the data files that have been lost. Then
issue the RECOVER TABLESPACE USERS command to recover the USERS tablespace. Use the
ALTER DATABASE DATAFILE 4 ONLINE command to bring the USERS tablespace online.
12. D. Since the online redo logs are intact, you will be able to use the NORESETLOGS version
of the CREATE CONTROLFILE command.
13. B. Since the database is in NOARCHIVELOG mode, their request cannot be met
because point-in-time recovery is supported only in ARCHIVELOG mode.
14. A, C. You can create a backup control file with the ALTER DATABASE BACKUP CONTROLFILE
command. You can create a trace file that contains the CREATE CONTROLFILE command.
15. A. First, you would want to restore the three data files that were lost. Then you would
want to issue the STARTUP MOUNT command to mount the database to prepare for recovery.
You would then recover the database (you could opt to recover just the data files if you
wished). Finally, open the database with the ALTER DATABASE OPEN command.