The datafiles of your database are ASM files. You are performing a check for datafile block corruption by using the DBVERIFY utility.  
What is a prerequisite for checking block corruption on an ASM datafile by using the DBVERIFY utility？（）  

单项选择题YouaremaintainingthePRODdatabaseofTeleSoftCorporation.YouhaveinitializedthefollowingDB_BLOCK_CHECKINGparameterintheinit.orafile：DB_BLOCK_CHECKING=TRUE；Whatwillbetheresultofsettingthisparameter？（）

A. Only data blocks of the SYSTEM tablespace will be checked.
B. Only data blocks of the SYSAUX tablespace will be checked.
C. A checksum will occur only on the checkpoint.
D. A checksum will occur every time a block is modified.

单项选择题YouareusingtheBlockMediaRecoveryfeaturetorecovertheblocksthataremarkedcorruptsincethelastbackup.Whichviewwillyouquerytodisplayinformationaboutthedatablocksthataremarkedcorruptsincethelastbackup？（）

A. V$BACKUP_CORRUPTION
B. V$COPY_CORRUPTION
C. V$DATABASE_BLOCK_CORRUPTION
D. RC_BACKUP_CORRUPTION

单项选择题YouaremaintainingyourOLTPdatabaseinOracle10g.YouareperformingtheFlashbackTransactionQuerytofindtheundoSQLstatementsthatcanbeusedtoundothechangesmadetothedatabaseinthespecifictimeperiod.WhichpseudocolumnwillyouusetoperformtheFlashbackTransactionQuery？（）

A. VERSIONS_STARTSCN
B. VERSIONS_STARTTIME
C. VERSIONS_XID
D. VERSIONS_OPERATION

单项选择题WhatwillbetheresultofusingtheSQL>DROPUSERSCOTTCASCADE；command？（）

A. The user， Scott， is dropped， all the objects in Scott’s schema are placed in the Recycle Bin， and the objects that are  already in the Recycle Bin are dropped.
B. The user， Scott， is dropped， all the objects in Scott’s schema are placed in the Recycle Bin， and all the objects in the Recycle Bin， belonging to the user Scott， are not dropped.
C. The user， Scott， is dropped， all the objects in the Scott’s schema are not placed in the Recycle Bin， and the objects in the Recycle Bin， belonging to the user， Scott， are not dropped.
D. The user， Scott， is dropped， all the objects in Scott’s schema are not placed in the Recycle Bin， and the objects in the Recycle Bin are dropped.

单项选择题You are performing flashback of the ORDERS table in the Scott’s schema because some important data is deleted in the table by mistake. The SCN number was 771513 at the time of deletion. You issued the following statement to perform Flashback Table：  SQL> FLASHBACK TABLE ORDERS TO SCN 771513；   What is the prerequisite to perform Flashback Table？（）

A. You must configure OMF in your database.
B. You must enable block change tracking feature in your database.
C. You must enable ROW MOVEMENT feature on the ORDERS table.
D. You must use the Flashback Version Query before using the Flashback Table feature.