多项选择题
You issue this SQL command to perform an online backup of the USER_DATA tablespace：ALTER TABLESPACE user_data BEGIN BACKUP；Next， you issue an operating system command to back up user_data01.dbf， the file that belongs to the USER_DATA tablespace. You then experience an instance failure. Which three statements are true？（）
A.A B.B C.C D.D E.E
单项选择题 WhichRMANcommandisusedtoverifythestatusofabackuporcopy，andalsoupdatestherepositorywhenfileshavebeendeletedusingoperatingsystemcommands？（）
单项选择题 UndertheOracleSharedServerarchitecture，client-userprocessesultimatelyconnecttoa（）
多项选择题 Whichtwoaretrueregardingdirect-pathexports？（）
