User SCOTT wants to back out the transactions on the REGIONS table in his schema. As a DBA， which commands must you execute to enable SCOTT to flash back the transactions？（）

单项选择题Examine the following RMAN script：   RMAN> run { debug on；  allocate channel c1 type disk； backup datafile 5； }   Which statement describes the purpose of the script？（）

A. The data file is checked for physical corruption and backed up if found clean.
B. The backup of data file 5 is performed and the interactive messages during the backup are suppressed.
C. The existing backup for the data file is checked and the backup is performed if there are changes in the data file after the last backup.
D. The backup of data file 5 is performed and all SQL statements that are executed during RMAN compilation and their results are displayed

单项选择题WhatdoestheDB_FLASHBACK_RETENTION_TARGETparameterconfigure？（）

A. An upper limit on how far you can flash back the database，depending on the information in the redo logs
B. An upper limit on how far you can flash back the database，depending on the information in the undo tablespace
C. The amount of time for which the flashback data is to be kept in the flash recovery area， provided that there is enough space
D. The amount of time for which the flashback data is guaranteed to be kept in the undo tablespace，provided that there is enough space

多项选择题WhichtwostatementsaretrueabouttheAutomaticDiagnosticRepository（ADR）？（）

A. The ADR base keeps all diagnostic information in binary format
B. SQL*Plus provides the ADRI script， which can be used to work with ADR
C. The ADR can be used for problem diagnosis only when the database is open
D. The ADR can be disabled by settting the DIAGNOSTIC_DEST parameter to null
E. The ADR can be used for problem diagnosis even when the database instance is down
F. The ADR base is shared across multiple instances

多项选择题YouwanttotakeacompletedatabasebackupusingRMAN.Thebackupshouldconsistonlytheusedblocksfromyourdatabase.Whichtwostatementsaretrueaboutthisbackupoperation？（）

A. Backup compression should be enabled
B. Parallelism for the channel should be set to 2
C. All the files must be backed up as backup sets
D. The backup may be stored either on disk or on media with media manager

多项选择题Whichoptionswouldyouconsiderwhileconfiguringaflashrecoveryareafastrecoveryareain11gRelease2foryourproductiondatabasethatisrunninginARCHIVELOGmode？（）

A. Setting the FAST_START_MTTR_TARGET to set the mean time to recover
B. Setting the RECOVERY_PARALLELISM parameter to twice the number of CPUs
C. Using the DB_RECOVERY_FILE_DEST parameter to set the location for flash recovery area
D. Using the DB_RECOVERY_FILE_DEST_SIZE parameter to define the disk space limit for the recovery files created in the flash recovery area