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