单项选择题
A.You performed rollback after commit.
B.If a log switch occurs in your database.
C.Thearchiverfails to generate an archived log file.
D.Instance recovery fails to find one of the redo log files.
E.A long-running query is unable to get read-consistent image.
F.If you perform manual undo management operations in auto mode.
单项选择题 You work as a database administrator for Certkiller .com. You added atablespaceto your database. Because of the changes to the physical structure of your database， you performed a backup of the control file to trace. After this， you lost only the control files and the instance aborted due to a hardware failure. How would you proceed to recover the database？（）
单项选择题 YouworkasadatabaseadministratorforCertkiller.com.Clientconnectionrequestsarefailingbecausethelistenerisnotresponding.Youwanttoforwardclientconnectrequeststoanotherlistenerifonelistenerisnotresponding.Howdoyouachievethis？（）
多项选择题 YouworkasadatabaseadministratorforCertkiller.com.YourdatabaseisintheMOUNTstateandyouexecutethefollowingcommandtoopenitALTERDATABASEOPEN；Whattwoactionsareperformedasaresultofthiscommand？（）