单项选择题
A. The redo log file should belong to an active group.
B. The redo log file should belong to an inactive group.
C. The redo log file should belong to the current group.
D. The redo log file can be dropped only if all the transactions are stopped.
E. Before a redo log file is dropped， it should be deleted from the operating system （OS）.
单项选择题 You are working in an online transaction processing （OLTP） environment. You used the FLASHBACK TABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command， the System Change Number （SCN） was 663571. After flashing back the CUSTOMERS table， you realize that the table is not in the correct state and the resultant changes are not what you had desired. So， you need to reverse the effects of the FLASHBACK TABLE command while ensuring that： a） No other user data in the database is affected. b） The operation takes the minimum possible time. Which option would you choose？（）
多项选择题 YourdatabaseisfunctioninginNOARCHIVELOGmode.Yourdatabasecontains15tablespaces.YouwanttouseRecoveryManager（RMAN）toperformbackups.Whichtwobackupswouldyoubeabletoperformwhenthedatabaseisbeingaccessedbyusers？（）
单项选择题 Inoneofyouronlinetransactionprocessing（OLTP）applications，mostusersfrequentlymodifythevalues，includingthekeyvalues，oftheapplicationtables.Someusersgenerateapplicationreportsbyusingmultipleapplicationtables.Whatisthebesttablestructurethatyoucanusetogainoptimalperformance？（）