You work as a database administrator for Certkiller .com. You are using Recovery Manager （RMAN） for backup and recovery of your database. You executed the delete command in RMAN to delete a backup of atablespace. Which statement is true in this scenario？（）

单项选择题YouworkasadatabaseadministratorforCertkiller.com.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You work as a database administrator for Certkiller .com. You need to rename a data file of atablespace.  How would you perform this？（）

A.A
B.B
C.C
D.D

多项选择题YouworkasadatabaseadministratorforCertkiller.com.Oneofthedatabaseusersaccidentallydeletedalltherowsofacriticaltableandcommittedthedeleteat1：30p.m.Youseniordatabaseadministrator，Certkiller，asksyoutoretrievethelostdata.Whichtwoactionswouldyouusetoensurethatthereisnoimpactonotherconnecteduserswhileretrievingthedeletedrows？（）

A.Use a flashback query to retrieve the rows that were deleted
B.Useconventialincremental export and then import the affected object
C.Shutdown the database inNORMALmode and restart the database instance
D.Use DBMS_META package to reconstruct the object using undo segments
E.UseTablespacePoint in Time Recovery （TSPITR） method to recover the table and the data
F.Use Oracle DataPumptwithflashback_timeoption toentableflashback export and then import the affected object.

单项选择题You work as a database administrator for Certkiller .com. When you tried to connect to the database， you received the following error： ERROR：  ORA-12541：TNS：no_listener  You found that the listener is not running on the server， so you issued the following command in the Listener Control utility to start the listener.  lsnrctl>START  What statement is true？（）

A.It would attempt to start the default listener
B.It would start the most recently created listener.
C.It would display an error with a message asking for the listener name to be specified.
D.It would show you a list of listeners and prompts for the listener name that you want to start.

单项选择题You execute the following command in your Certkiller .com production database to change the width of the CUST_NAME column of the CUSTOMERS table： ALTER TABLE customers  MODIFY （cust_nameVARCHAR2 （40））    When you execute the command， it displays the following error message：  ERROR at line 1：  ORA-00054： resource busy and acquire with NOWAIT specified  What could be the reason for the error message？（）

A.The database instance is not available.
B.The ALTER TABLE command does not have WAIT option
C.The table or a row in the table is currently locked by another user session.
D.The database instance is busy processing other user sessions commands.
E.The CUSTOMERS table has no long running query active at the time when this request is made.
F.The server process executing the ALTER TABLE command is busy with another command execution