基于时间的不完全恢复数据库过程出错

ALLSTARS_ORACLE

rman>backup database;---全备数据库
创建表 tb_time，插入数据
21:18:29 SQL> update tb_time set name='hkny-002' where id=2;
21:18:47 SQL> commit;
21:19:07 SQL> drop table tb_time;

[oracle@oracle10g ~]$ export ORACLE_SID=wilson
[oracle@oracle10g ~]$ export NLS_DATE_FORMAT="YYYY-MM-DD HH24:MI:SS"
[oracle@oracle10g ~]$ export NLS_LANG="AMERICAN"
[oracle@oracle10g ~]$ rman target sys/oracle
RMAN> RUN{
2> shutdown abort;
3> startup mount;
4> SET UNTIL TIME='2011-03-11 21:18:47';
5> RESTORE DATABASE;
6> RECOVER DATABASE;
7> ALTER DATABASE OPEN RESETLOGS;}
。。。。。。。。。。。。。。。。
channel ORA_DISK_1: restored backup piece 29
piece handle=/u01/oracle/db_back/2am6vts4_29_1 tag=TAG20110311T210923
channel ORA_DISK_1: reading from backup piece /u01/oracle/db_back/2am6vts4_30_1
channel ORA_DISK_1: restored backup piece 30
piece handle=/u01/oracle/db_back/2am6vts4_30_1 tag=TAG20110311T210923
channel ORA_DISK_1: reading from backup piece /u01/oracle/db_back/2am6vts4_31_1
channel ORA_DISK_1: restored backup piece 31
piece handle=/u01/oracle/db_back/2am6vts4_31_1 tag=TAG20110311T210923
channel ORA_DISK_1: restore complete, elapsed time: 00:04:42
failover to previous backup

Finished restore at 2011-03-11 21:28:35

Starting recover at 2011-03-11 21:28:36
using channel ORA_DISK_1

starting media recovery
Oracle Error:
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 5 needs more recovery to be consistent
ORA-01110: data file 5: '/u01/oradata/wilson/example01.dbf'

media recovery complete, elapsed time: 00:00:06

Finished recover at 2011-03-11 21:28:47
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of alter db command at 03/11/2011 21:28:47
ORA-01194: file 5 needs more recovery to be consistent
ORA-01110: data file 5: '/u01/oradata/wilson/example01.dbf'

问题：1）restore成功了没有？failover to previous backup什么意思？如果有问题为什么还显示channel ORA_DISK_1: restore complete, elapsed time: 00:04:42，Finished restore at 2011-03-11 21:28:35
         2）recovery到底成没成功？
        3）出错显示ORA-01194: file 5 needs more recovery to be consistent是什么意思？怎样解决这个问题？
        先谢谢各位高手了



restore database until time '2011-03-11 21:18:47' preview;
recover database；
alter database open;
把数据库起来了
请问，1）这个应该是不完全恢复啊，为什么用alter database open resetlog;不能打开数据库呢？
          2）preview在你的语句里起什么作用啊，是不是可有可无啊？
        3)数据库打开了，可是表tb_time没了，也就是说恢复失败，怎么才能成功？



还有就是它提示的出错显示ORA-01194: file 5 needs more recovery to be consistent，我的file 5是EXAMPLE表空间，在rman中是排出备份的，
CONFIGURE EXCLUDE FOR TABLESPACE 'EXAMPLE';
CONFIGURE EXCLUDE FOR TABLESPACE 'STAGING';
请问在做不完全恢复之前，做数据库全备时，是不是应该把EXAMPLE和STAGING两个表空间的排出备份取消，在做数据库全备时，把这两个表空间也都备份进去?然后在做基于时间的不完全恢复?