下列叙述错误的是（)A．高频无线电信号由天线发出后，沿两条路径在空间传播B．微波天线的高度方向

uspectthelackofindexestobethereasonforthedegradationinperformance.Whichadvisorycomponentwouldyoureferto，inordertodeterminetheappropriateindexes？（）

A.MemoryAdvisor

B.SegmentAdvisor

C.SQLAccessAdvisor

D.AutomaticWorkloadRepository（AWR）

E.AutomaticDatabaseDiagnosticMonitor（ADDM）

A. The SGA Tuning Advisor

B. The SQL Access Advisor

C. The SQL Tuning Advisor

D. The Memory Advisor

A. The incident metadata is purged when the problem is resolved and the DBA closes the SR

B.The incident files and dumps are not retained in the ADR for the manually created incidents

C. The incident files are retained but the incident metadata is purged when the problem is resolved and the DBA closes the SR

D. The default setting is for one year after which the incident metadata is purged from the ADR and the files are retained for one month

Givenacompletelossofyourdatabase，inwhatorderwouldyouneedtoperformthefollowingRMANoperationstorestoreit？（）a.restorecontrolfileb.restoredatabasec.restorespfiled.recoverdatabasee.alterdatabaseopenf.alterdatabaseopenresetlogs

A.b，a，c，d，e

B.a，c，b，d，f

C.c，a，b，d，e

D.c，a，b，d，f

E.e，a，b，d，c

dmethodtoperformthistask.Thetableinwhichyouplantoloaddataisanimportanttablehavingvariousintegrityconstraintsdefinedonit.Whichconstraintswillremainenabledbydefaultduringthisoperation（）

A.CHECK

B.UNIQUE

C.NOTNULL

D.PRIMARYKEY

E.FOREIGNKEY

A. The Memory Advisor

B. The SQL Tuning Advisor

C. The Undo Advisor

D. The SQL Access Advisor

A.Youperformedrollbackaftercommit.

B.Ifalogswitchoccursinyourdatabase.

C.Thearchiverfailstogenerateanarchivedlogfile.

D.Instancerecoveryfailstofindoneoftheredologfiles.

E.Along-runningqueryisunabletogetread-consistentimage.

F.Ifyouperformmanualundomanagementoperationsinautomode.

seofthechangestothephysicalstructureofyourdatabase，youperformedabackupofthecontrolfiletotrace.Afterthis，youlostonlythecontrolfilesandtheinstanceabortedduetoahardwarefailure.Howwouldyouproceedtorecoverthedatabase？（）

A.Starttheinstanceandopenthedatabase，instancerecoveryautomaticallyrecoverscontrolfiles

B.Createafilebasedonthecontentsofthetracefileandsaveittothecontrolfilelocationsandstartthedatabase

C.Re-createthedatabase（Therecoveryofthecontrolfileisnotpossiblebecauseyouhavelostallthecontrolfiles.）

D.Starttheinstance，intheNOMOUNTstate，re-createthecontrolfileusingtheCREATECONTROLFILEcommandstoredinthetracefile.

E.StarttheinstanceandMOUNTthedatabase，thenre-createthecontrolfileusingtheCREATECONTROLFILEcommandstoredinthetracefile.

t to perform user managed backup for the data files of the HR_DATA tablespace.To accomplish the task, you issued the following command:SQL> ALTER TABLESPACE hi_data BEGIN BACKUP;Which two statements are true in this scenario? （）

A. No transaction on the tablespace is allowed but you can perform queries.

B. The tablespace will automatically come out of backup mode when the file copy is complete.

C. The checkpoint change number is frozen in headers of the data files until the file is removed from backup mode.

D. The database writes the before image of an entire block to the redo stream before modifying. block tor the first time.

Observetheinformationinthecolumns：1.TheSGAa.TextandparsedformsofallSQLstatements2.Thecursorstateb.Run-timememoryvaluesfortheSQLstatement，suchasrowsretrieved3.User-sessiondatac.Securityandresourceusageinformation4.Thestackspaced.LocalvariablesfortheprocessWhichoptionhasthecorrectmatchbetweenthememoryareasandtheircontents（）

A.1-c，2-b，3-d，4-a

B.1-b，2-c，3-d，4-a

C.1-a，2-b，3-c，4-d

D.1-a，2-b，3-d，4-c