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You are managing an Oracle Database 11g database. The database is open, and you plan to perform
Recovery Manager (RMAN) backups. Which three statements are true about these backups? (Choosethree.)
A.The backups would be consistent.
B.The backups would be inconsistent.
C.The backups would be possible only if the database is running in ARCHIVELOG mode.
D.The backups would be possible only if the database is running in NOARCHIVELOG mode.
E.The backups need to be restored and the database has to be recovered in case of a media failure.

一致性备份需要在shut down状态，所以B正确。
归档状态下支持热备，C正确。
E选项：
　　说的是介质有问题了，备份必须 restore 然后 recovered，这里说一下 restore 和 recover 的区别
　　restore：从备份位置还原一个或者多个数据库文件
　　recover:应用归档和联机重做日志文件，将整个数据库或单独数据库文件前滚到指定的 scn
　　这就是归档文件的作用，当执行备份的时候，只是备份到一个点的数据，但是在备份之后这段时间执行的数据，就需要通过 recover 利用归档日志，来进行前滚实现，因此需要这两步