单项选择题
A. Yes， if the database is in ARCHIVELOG mode
B. Yes， if the database is in NOARCHIVELOG mode
C. No， the backup is not usable in any way
D. Only if the ENABLE_ONLINE_BACKUP parameter is set to TRUE
单项选择题 WhichofthefollowingisavalidwayofputtingatablespacenamedDAVE_TBSintohotbackupmode？（）
单项选择题 Whichcommandwillresultinatracefilebeingcreatedwiththecreatecontrolfilecommandcontainedinit？（）
单项选择题 What is the correct order of steps to perform an online database backup？（） a. alter database begin backup b. alter database end backup c. Back up the database datafiles d. Back up the archive log files e. alter system switch logfile