Which two operations require undo data？（）

多项选择题WhichtwostatementsaretrueregardingthedatabaseinARCHIVELOGmode？（）

A.You have to shut down the database to perform the backups.
B.Archiving information is written to the data files and redo log files.
C.You can perform complete database backups without closing the database.
D.Online redo log files have to be multiplexed before putting the database in ARCHIVELOG mode.
E.All the previous database backups become invalid after you configure the database to ARCHIVELOG mode.

单项选择题Becauseofapoweroutage，instancefailurehasoccurred.Fromwhatpointintheredologdoesrecoverybeginandwheredoesitend？（）

A.current redo log and inactive redo log
B.checkpoint position to end of redo log
C.beginning of redo log to end of redo log
D.all redo logs before the point of last commit
E.beginning of redo log to checkpoint position

单项选择题WhichstepdoyouneedtoperformtoenableauserwiththeSYSDBAprivilegetologinasSYSDBAiniSQL*Plus？（）

A.The user must be granted the database administrator （DBA） privilege.
B.The user must be listed in the password file for the authentication.
C.No special setup is needed for the user to connect as SYSDBA in iSQL*Plus.
D.Set up a user in the Oracle Application Server Containers for J2EE （OC4J） user manager，and grant the webDba role to the user.

单项选择题Accordingtoyourbackupstrategy，youperformedanincrementallevel0backupofyourdatabase.Whichstatementregardingthisbackupistrue？（）

A.The backup is similar to image copy.
B.The backup contains all used data blocks.
C.The backup contains only unused data blocks.
D.The backup contains all data blocks changed since the last incremental level 1 backup.

单项选择题WhichstatementregardingthecontentsoftheV$PARAMETERviewistrue？（）

A.displays only the list of default values
B.displays only the list of all basic parameters
C.displays the currently in effect parameter values
D.displays only the list of all advanced parameters
E.displays the list of all the parameter files of a database