Your database has experienced a loss of datafile users_01.dbf, which is associated with a ablespace called USERS. The database is still running. Which answer properly describes the rder of the steps that you would use to recover from this error?
1. Shut down the database.
2. Take the users_01.dbf datafile offline with the alter database command.
3. Restore the users_01.dbf datafile from backup media with the required archived redo logs.
4. Restore all users tablespace-related datafiles from backup media.
5. Issue the recover tablespace users command.
6. Issue the recover datafile users_01.dbf command.
7. Start up the database.
8. Bring the users_01.dbf datafile online with the alter database command.
A.1, 3, 6, 7
B.2, 3, 6, 8
C.1, 2,3,6,7
D.1, 2, 3, 6, 7, 8
E.2, 3,6,5,7
First you would take the users_01.dbf datafile offline.You would then restore the users_01.dbf datafile from the most current backup.Once you have restored the datafile,recover the datafile with the recover datafile command.Finally,bring the datafile online with the alter database command.
注:users01.dbf不是关键数据文件，所以这里用offline来修复。
原文：http://www.cnblogs.com/Babylon/p/7805206.html