优点是水位波动振幅小衰减快，需要调压室的容积小，且引水系统与其接头处的水头损失小；缺点是反射

A．functions

B．package

C．procedure

D．databasetrigger

E．anonymousPL/SQLblock

A. It bypasses the OS file system cache.

B. A separate NFS interface is required for use across Linux, UNIX, and Windows platforms.

C. It uses the operating system kernel NFS layer for user tasks and network communication modules.

D. File systems need not be mounted by the kernel NFS system when being served through Direct NFS.

E. Oracle Disk Manager can manage NFS on its own, without using the operating system kernel NFS driver.

for a SQL statement but does not find a matching plan in the SQL plan baseline.Which two operations are performed by the optimizer in this scenario?（）

A. The optimizer adds the new plan to the plan history.

B. The optimizer selects the new plan for the execution of the SQL statement.

C. The optimizer adds the new plan to the SQL plan baseline as an accepted plan.

D. The optimizer adds the new plan to the SQL plan baseline but not in the ENABLED state.

E. The optimizer costs each of the accepted plans in the SQL plan baseline and picks the one with the lowest cost.

A.YoucanuseRMANstoredscripts.

B.Recoveryisfasterifdataisstoredincataloginadditiontothecontrolfile.

C.YoucanstorebackupInformationofallregistereddatabasesinoneplace.

D.Databasebackupsareautomaticallydeletedwhentheyareolderthanthespecifiedtimeperiod.

A.java.lang.StackOverflowError

B.java.lang.IllegalStateException

C.java.lang.ExceptionInInitializerError

D.java.lang.ArrayIndexOutOfBoundsException

ions：SQL>UPDATEempSETsal=sal*1.15WHEREdeptno=20BeforeSCOTTendsthetransaction，userHRwhohastheprivilegesonEMPtableexecutesaquerytofetchthesalarydetailsbutfindstheoldsalaryvaluesinsteadoftheincreasedvalues.WhydoesHRstillseetheolddata？（）

A.becauseofredodatafromredologfile

B.becauseofdatafromdatabasebuffercache

C.becauseofdatafromatemporarytablespace

D.becauseofundodatafromtheundotablespace

AdatabaseisrunningInARCHIVBXXMSmode.Ithastwoonlineredologgroupsandeachgrouphasonemember.

ALGWRInput/output（I/O）fellsduetopermanentmediafailurethathasresultedInthelossofredologfileandtheLWGRterminatescausingtheinstancetocrash.Thestepstorecoverfromthelossofacurrentredologgroupmemberintherandomorderareasfollow.

1）Restorethecorruptedredologgroup.

2）Restorefromawholedatabasebackup.

3）Performincompleterecovery.

4）Relocatebyrenamingthememberofthedamagedonlineredologgrouptoanewlocation.

5）OpenthedatabasewiththeRESETLOGSoption.

6）Restartthedatabaseinstance.

7）Issueacheckpointandclearthelog.

Identifytheoptionwiththecorrectsequentialstepstoaccomplishthetaskefficiently（）.

A. Only a single partitioning key column can be specified.

B. All DML statements must use partition-extended syntax.

C. The same physical attributes must be specified for each partition.

D. Unique local indexes cannot be created on a system-partitioned table.

E. Traditional partition pruning and partitionwise joins are not supported on these tables.

Notetheoutputofthefollowingquery；SQL>SELECTflashback_archieve_name，statusFROMdba_flashback_archieve；FLASHBACK_ARCHIEVE_NAMESTATUSFLA1YouexecutedthefollowingcommandtoenableFlashbackDataArchiveontheEXCHANGB_PATEtable：ALTERTABLEexchange_rateFLASHBACKARCHIEVE；Whatistheoutcomeofthiscommand？（）

A.ThetableusesthedefaultFlashbackDataArchive.

B.TheFlashbackDataArchiveIscreatedIntheSYSAUXtablespace.

C.TheFlashbackDataArchiveiscreatedinthesametablespacewherethetablesarestored.

D.ThecommandgeneratesanerrorbecausenoflashbackDataArchivenameisspecifiedandthereis nodefaultFlashbackDataAchieve.

Inyourproductiondatabase，youhaveobservedthatthedatabaseserverperformancedegradeswheneverthereisaswitchbetweentheloggroups.Onfurtherinvestigation，youfindthatthedatabaseisrunninginARCHIVELOGmodeandthearchivedlogfilesarebeingwrittentothesamediskthatisusedtostoretheredologmembers.Whichtwoactionswouldyoutaketoimprovetheperformanceofthedatabaseserver？（）

A.increasethesizeoftheredologbuffer

B.increasethenumberofredologgroups

C.increasethenumberoflogwriterprocesses

D.increasethenumberofARCnprocesses

E.changetheappropriateLOG_ARCHIVE_DEST_nparametertoplacethearchivedlogfilesinaseparatelocation