323.What is the correct order of the following commands if you wanted to restore datafile 4, which was
accidentally removed from the file system?
A. sql 'alter database datafile 4 online';
B. restore datafile 4;
C. recover datafile 4;
D. sql 'alter database datafile 4 offline';
E. startup
F. shutdown
G. a, c, b, d
H. d, b, c, a
I. f, d, b, c, a, e
J. c, a, b, d, f
K. a, b, d, e
Answer: B
答案解析：
此题的选项有点问题，故从另一套找来正确的题。
按题意：数据文件4不小心被删除，现在需要恢复，以下是恢复步骤：
1、实验之前需要先备份：
RMAN> backup datafile 4;
Starting backup at 23-SEP-13
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00004 name=/u01/app/oracle/oradata/test0910/users01.dbf
channel ORA_DISK_1: starting piece 1 at 23-SEP-13
channel ORA_DISK_1: finished piece 1 at 23-SEP-13
piece handle=/u01/app/oracle/fast_recovery_area/TEST0910/backupset/2013_09_23/o1_mf_nnndf_TAG20130923T100457_940ln9o6_.bkp tag=TAG20130923T100457 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 23-SEP-13
2、模拟不小心删除
[oracle@rtest test0910]$ rm /u01/app/oracle/oradata/test0910/users01.dbf
3、开始恢复
RMAN> sql 'alter database datafile 4 offline';
using target database control file instead of recovery catalog
sql statement: alter database datafile 4 offline
RMAN> restore datafile 4;
Starting restore at 23-SEP-13
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=224 device type=DISK
channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/test0910/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/fast_recovery_area/TEST0910/backupset/2013_09_23/o1_mf_nnndf_TAG20130923T100457_940ln9o6_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/fast_recovery_area/TEST0910/backupset/2013_09_23/o1_mf_nnndf_TAG20130923T100457_940ln9o6_.bkp tag=TAG20130923T100457
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 23-SEP-13
RMAN> recover datafile 4;
Starting recover at 23-SEP-13
using channel ORA_DISK_1
starting media recovery
media recovery complete, elapsed time: 00:00:01
Finished recover at 23-SEP-13
RMAN> sql 'alter database datafile 4 online';
sql statement: alter database datafile 4 online