多项选择题
A. A tablespace is taken offline.
B. The database instance is restarted.
C. A new data file is added to an existing tablespace.
D. A successful backup is recorded in the RMAN repository.
E. The RMAN connection is disconnected from the target database.
单项选择题 YouexecutethefollowingRMANcommandintheordershownbelow：BACKUPVALIDATEDATABASE；BLOCKRECOVERCORRUPTIONLIST；Whatwillthesecommandsdo？（）
单项选择题 Whatpurposewouldyouachievebyenablingtheblockchangetrackingfeature？（）
单项选择题 Adatafilebecomecorruptedinyourdatabaseduetobadsectorsonthedisk.Becauseofcorruption，youlostalltheimportanttablesinthatdatafile.Whichmethodwouldyouuseforrecovery？（）