基于时间（time）恢复
基于时间的恢复将数据库恢复到备份点与失败点之间的某个时间点。基于时间的恢复不仅在介质失败的时候使用，也可以在数据库正常运行的时候使用。例如：某个用户误删除了某个表的数据，这个时候我们可以通过基于时间的恢复来将删除的数据恢复出来，示例如下：
1、查看当前用户下的表，只有一张WWL001
21:07:31 SQL> select * from tab;
TNAME TABTYPE CLUSTERID
------------------------------ -----------------
WWL001 TABLE
Elapsed: 00:00:00.06
我们通过WWL001来创建WWL002-WWL005 共四张表用来测试不完全恢复
21:08:28 SQL> create table wwl002 asselect * from wwl001;
Table created.
Elapsed: 00:00:00.17
21:08:55 SQL> create table wwl003 asselect * from wwl001;
Table created.
Elapsed: 00:00:00.04
21:09:00 SQL> create table wwl004 asselect * from wwl001;
Table created.
Elapsed: 00:00:00.03
21:09:06 SQL> create table wwl005 asselect * from wwl001;
Table created.
Elapsed: 00:00:00.05
如上表已经创建完成
2、我们在21:13:13开始删除表（请注意时间）
21:13:13 SQL> drop table wwl002 purge;
Table dropped.
Elapsed: 00:00:00.16
21:13:28 SQL> drop table wwl003 purge;
Table dropped.
Elapsed: 00:00:00.11
21:13:34 SQL> truncate table wwl004;
Table truncated.
Elapsed: 00:00:00.32
21:13:44 SQL> truncate table wwl005;
Table truncated.
Elapsed: 00:00:00.07
21:13:47 SQL>
因为我们是要做基于时间的恢复，那么我们只有将数据库恢复到21:13:13之前的这个时间段，才能把我们刚才创建的表找回来。
3、开始执行恢复，先将数据库启动到mount状态
21:14:40 SQL> conn / as sysdba
Connected.
21:14:44 SQL> shutdown immediate
Database closed.
Database dismounted.
21:15:20 SQL> startup mount;
ORACLE instance started.
Total System Global Area 100663296 bytes
Fixed Size 1217884 bytes
Variable Size 88083108 bytes
Database Buffers 8388608 bytes
Redo Buffers 2973696 bytes
Database mounted.
21:15:46 SQL> e
4、开始执行restore到备份数据库的当前状态：
RMAN> restore database;
Starting restore at 12-JUL-12
using target database control file insteadof recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=47 devtype=DISK
channel ORA_DISK_1: starting datafilebackupset restore
channel ORA_DISK_1: specifying datafile(s)to restore from backup set
restoring datafile 00001 to/DBBak2/oradata/WWL/system01.dbf
restoring datafile 00002 to/DBBak2/oradata/WWL/undotbs01.dbf
restoring datafile 00003 to/DBBak2/oradata/WWL/sysaux01.dbf
restoring datafile 00004 to/DBBak2/oradata/WWL/users01.dbf
restoring datafile 00005 to/DBBak2/oradata/WWL/wwl01.dbf
restoring datafile 00006 to/DBBak2/oradata/WWL/wwl02.dbf
restoring datafile 00007 to/DBBak2/oradata/WWL/wwl03.dbf
channel ORA_DISK_1: reading from backuppiece /DBSoft/product/10.2.0/db_1/dbs/01nft4mu_1_1
channel ORA_DISK_1: restored backup piece1
piecehandle=/DBSoft/product/10.2.0/db_1/dbs/01nft4mu_1_1 tag=TAG20120712T095437
channel ORA_DISK_1: restore complete,elapsed time: 00:01:35
Finished restore at 12-JUL-12
RMAN> exit
5、执行基于时间点的恢复：
21:27:54 SQL> recover database untiltime ‘YYYY-mm-dd hh24:mi:ss’
21:27:54 SQL> recover database untiltime '2012-07-12 21:10:00';
ORA-00279: change 1436429 generated at07/12/2012 09:54:38 needed for thread 1
ORA-00289: suggestion :/DBSoft/product/10.2.0/db_1/dbs/arch1_3_788372282.dbf
ORA-00280: change 1436429 for thread 1 isin sequence #3
21:30:09 Specify log:{
auto
ORA-00279: change 1440657 generated at 07/12/201214:00:52 needed for thread 1
ORA-00289: suggestion :/DBSoft/product/10.2.0/db_1/dbs/arch1_1_788450452.dbf
ORA-00280: change 1440657 for thread 1 isin sequence #1