下列属于地下水的动态特征的是（)。A．容水性B．流向C．水位随时间的变化规律D．物理性质

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

c.Youexecutedthefollowingcommandtoenableretentionguarantee：SQL>ALTERTABLESPACEundotbs1RETENTIONGUARANTEEWhateffectwouldthisstatementhaveonthedatabase？（）

A.Theextentsinundotablespaceretaindatauntilthenextfulldatabasebackup.

B.Theextentscontainingcommitteddataintheundotablespaceareneveroverwritten.

C.Theextentswhichnolongercontainuncommitteddataintheundotablespacearenotoverwrittenforatleast15minutes.

D.Theextentscontainingcommitteddataintheundotablespacearenotoverwrittenuntiltheinstanceisshutdown.

A. It enables all system triggers.

B. It allows only SYSDBA connections.

C. It ensures that all job queues remain active during the upgrade process.

D. It sets system initialization parameters to specific values that are required to enable database upgrade scripts to be run.

A.ANALYZEoperations

B.dbv

C.SQLqueriesthataccessthepotentiallycorruptblock

D.RMAN

E.Alloftheabove

A.increasethesizeofredologfiles

B.increasethesizeoftheundotablespace

C.increasethesizeoftheDatabaseBufferCache

D.increasethesizeofthedefaulttemporarytablespace

E.enabletheretentionguaranteefortheundotablespace