单项选择题
A. The backup set has exceeded the retention criteria set in RMAN and is eligible for removal.
B. The backup set has one or more invalid blocks in it and is not usable for recovery.
C. The backup set contains one or more tablespaces no longer in the database.
D. The backup set contains one or more missing backup set pieces.
E. The backup set is from a previous version of RMAN and was not upgraded.
多项选择题 Whywouldyourunthedeleteobsoletecommand？（）
单项选择题 You run the following commands： RMAN> list expired backup； RMAN> delete expired backup； What will happen to the backup set pieces associated with the backups that appear in the list expired backup command？（）
单项选择题 You have lost all your RMAN backup set pieces due to a disk failure. Unfortunately， you have an automated cross-check script that also does a delete expired backupset command. You have restored all the backup set pieces from tape. What command would you use to get those backup set pieces registered in the recovery catalog and the control file of the database again？（）