2024年计算机考试-Oracle认证笔试考试历年高频考点试题摘选含答案

2024年计算机考试-Oracle认证笔试考试历年高频考点试题摘选含答案第1卷一.参考题库(共75题)1.You have a read/x7fonly tablespace on read/x7fonly media. You want to perform a media recovery on the existing data files， but using a backup control file. The backup control file indicates that the status of the read/x7fonly tablespace was read/write when the control file was backed up. What should you consider？（）A、drop the read­only tablespace and re­create the tablespace after recoveryB、take data files from the read­only tablespace offline before performing a recoveryC、perform a recovery; status of the tablespace in control file will be changed automaticallyD、recovery using backup control file is not possible， so restore all the files from the last full database backup， and then open the database2.What are the consequences of executing the SHUTDOWN ABORT command？ （）A、The database files are synchronized.B、Uncommitted changes are not rolled back.C、The database is closed， but the instance is still started.D、Database buffers and redo buffers are not written to the disk.E、The database undergoes automatic media recovery during the next startup.3.下列哪个子句实现对一个结果集进行分组和汇总？（）A、HAVINGB、ORDERBYC、WHERED、GROUPBY4.Given: Whatistheresult?（）A、2B、3C、4D、6E、75.可以使用（）伪列来访问序列。A、CURRVAL和NEXTVALB、NEXTVAL和PREVALC、CACHE和NOCACHED、MAXVALUE和MINVALUE6.There was media failure and you need to check the data files for any block corruption. Which option would you use to create a report on any corruptions found within the database？（） A、the DBNEWID utilityB、the DBVERIFY utilityC、the ANALYZE commandD、the RMAN REPORT commandE、the RMAN CROSSCHECK commandF、the CHECK_OBJECT procedure of the DBMS_REPAIR package7.You find that the database performance degrades while you backup the PROD database using Recovery Manager （RMAN）. The PROD database is running in shared server mode. The database instance is currently using 60% of total operating system memory. You suspect the shared pool fragmentation to be the reason. Which action would you consider to overcome the performance degradation？（）A、Configure Java Pool to cache the java objects.B、Configure Streams Pool to enable parallel processing.C、Increase Shared Pool size to cache more PL/SQL objects.D、Increase Database Buffer Cache size to increase cache hits.E、Configure Large Pool to be used by RMAN and shared server.F、Increase the total System Global Area （SGA） size to increase memory hits.8.Which three resource plan parameters are used to enable Automatic Consumer Group Switching to estimate job execution times automatically， and to perform a switch to a low priority consumer group before they are initiated？（）A、SWITCH_TIMEB、SWITCH_GROUPC、MAX_SESS_POOLD、SWITCH_ESTIMATE9.下列哪个函数可以把一个列中的所有值相加求和？（）A、MAXB、SUMC、COUNTD、AVG10.授予sa用户在SCOTT.EMP表中SAL列的更新权限的语句是（）。A、GRANTCHANGEONSCOTT.EMPTOSAB、GRANTUPDATEONSCOTT.EMP（SAL）TOSAC、GRANTUPDATE（SAL）ONSCOTT.EMPTOSAD、GRANTMODIFYONSCOTT.EMP（SAL）TOSA11.You work as a database administrator for S. Because of space constraints， you decided to manually shrink the table. You executed the ALTER TABLE SHRINK SPACE statement to shrink the space and you receive an error as follows：   ERROR at Line 1：   ORA-10635： Invalid segment or tablespace type   What could be the reason？ （）A、The table is partitionedB、The table name is wrong.C、It is an index-Organized table （IOT）D、The table is stored in locally managedtablespace.E、The table is stored in atablespacewhere segment space is managed manually.12.写出ORACLE的四种文件。（从物理存储结构分析）13.You use the Memory Advisor to tune the memory structures of your database. What is the prerequisite to use the Memory Advisor？（）A、 The database must be in the ARCHIVELOG mode.B、 The automatic memory tuning must be enabled.C、 The change tracking feature must be enabled.D、 The automatic memory tuning must be disabled.14.While creating a scheduler window using the DBMS_SCHEDULER package， a user logged in as DBMGR gets the error message insufficient privileges.  Which two commands would you use to resolve this error？（）A、GRANT dba TO dbmgr;B、GRANT connect TO dbmgr;C、GRANT resource TO dbmgr;D、GRANT hs_admin_role TO dbmgr;E、GRANT manage scheduler TO dbmgr;15.Your database is functional with a peak load for the last one hour. You want to preserve the performancestatistics collected during this period to be used for comparison when you analyze the performance of thedatabase in the future.  What action would you take to achieve this task（）A、Insert finding directives for ADDM tasks in the future.B、Create a baseline on a pair of snapshots spanning the peak-load period.C、Decrease the snapshot interval in the AWR to collect more snapshots during the peak- load period.D、Set the snapshot retention period in the Automatic Workload Repository （AWR） to zero to avoid automaticpurging of snapshots16.Given: Whichcode,insertedatline14,allowstheSpriteclasstocompile?（）A、Directiond=NORTH;B、Nav.Directiond=NORTH;C、Directiond=Direction.NORTH;D、Nav.Directiond=Nav.Direction.NORTH;17.You are in the middle of a transaction updating a very important table. The machine on which a database wasrunning reboots because of power outage. This caused a database instance failure. Which statement is true inthis situation（）A、The online redo log files and archived redo log files are required to accomplish the recovery.B、The uncommitted transaction will be committed at the next startup of the database instance.C、The uncommitted transaction is rolled back automatically at the next opening of the database.D、The DBA has to perform the recovery on the database to recover the uncommitted transaction18.Given: Whatistheresult?（）A、6B、7C、10D、11E、Compilationfails.F、Anexceptionisthrownatruntime.19.WhichthreestatementsaretrueaboutOracleDataPumpexportandimportoperations?（）A、Youcandetachfromadatapumpexportjobandreattachlater.B、Datapumpusesparallelexecutionserverprocessestoimplementparallelimport.C、Datapumpimportrequirestheimportfiletobeinadirectoryownedbytheoracleowner.D、Themastertableisthelastobjecttobeexportedbythedatapump.E、Youcandetachfromadatapumpimportjobandreattachlater.20.WhichthreeoperationscanbeperformedasmultipartitionoperationsinOracle?（）A、MergepartitionsofalistpartitionedtableB、DroppartitionsofalistpartitionedtableC、Coalescepartitionsofahash-partitionedglobalindex.D、Movepartitionsofarange-partitionedtableE、RenamepartitionsofarangepartitionedtableF、Mergepartitionsofareferencepartitionedindex21.ExaminethestructureoftheEMP_DEPT_VUview: ColumnNameTypeRemarks EMPLOYEE_IDNUMBERFromtheEMPLOYEEStable EMP_NAMEVARCHAR2(30)FromtheEMPLOYEEStable JOB_IDVARCHAR2(20)FromtheEMPLOYEEStable SALARYNUMBERFromtheEMPLOYEEStable DEPARTMENT_IDNUMBERFromtheDEPARTMENTStable DEPT_NAMEVARCHAR2(30)FromtheDEPARTMENTStable WhichSQLstatementproducesanerror?（）A、SELECT*FROMemp_dept_vu;B、SELECTdepartment_id,SUM(salary)FROMemp_dept_vuGROUPBYdepartment_id;C、SELECTdepartment_id,job_id,AVG(salary)FROMemp_dept_vuGROUPBYdepartment_id,job_id;D、SELECTjob_id,SUM(salary)FROMemp_dept_vuWHEREdepartment_idIN(10,20)GROUPBYjob_idHAVINGSUM(salary)>20000E、Noneofthestatementsproduceanerror;allarevalid.22.WhichfouraretypesoffunctionsavailableinSQL?（）A、stringB、characterC、integerD、calendarE、numericF、translationG、dateH、conversion23.Whichsubstitutionvariablewouldyouuseifyouwanttoreusethevariablewithoutpromptingtheusereachtime?（）A、&B、ACCEPTC、PROMPTD、&&24.You want to convert your existing non-ASM files to ASM files for the database PROD.  Which method or command would you use to accomplish this task？（）  A、 Data Pump Export and ImportB、 conventional export and importC、 the CONVERT command of RMAND、 the BACKUP AS COPY. command of RMAN25.（）方式的导出会从指定的表中导出所有的数据。A、分区B、表C、全部数据库D、表空间26.Given： When line 14 is reached， how many objects are eligible for the garbage collector？（）A、0B、1C、2D、3E、427.Whichthreestatementsaretrueaboutpersistentconfiguration?（）(Choosethree.)A、AusercannotsetprivilegesonthepersistentlightweightjobsB、PersistentlightweightjobsgeneratealargeamountofmetadataC、Itispossibletocreatefullyself-containedpersistentlightweightjobsD、TheuseofatemplateismandatorytocreatepersistentlightweightjobsE、Persistentlightweightjobsareusefulwhenusersneedtocreatealargenumberofjobsinashorttime28.In your S database server the parameter PLSQL_CODE_TYPE has been set to NATIVE. Which object would be achieved by the setting？（）A、The source PL/SQL code will be stored in native machine code.B、The source PL/SQL code will be stored in interpreted byte code.C、The compiled PL/SQL code will be stored in native machine code.D、The compiled PL/SQL code will be stored in interpreted byte code.29.What are the prerequisites for enabling Flashback Database？ （）A、 The database must be started in the MOUNT EXCLUSIVE state.B、 The database must have multiplexed control files.C、 The database must be opened by using a text-based parameter file instead of a server parameter file （SPFILE）.D、 The database must be in ARCHIVELOG mode.E、 The database must be in the NOMOUNT state.F、 The database must be opened in RESTRICTED mode.30.You work as a database administrator for Certkiller .com. In a production environment， users complain about the slow response time when accessing the database. You have not optimized the memory usage of the Oracle instance and you suspect the problem to be with the memory. To which type of object would you refer to determine the cause of the slow response？（）A、The trace fileB、The fixed viewsC、The data dictionary viewsD、The operating system log fieldsE、The dynamic performance views.31.Whatistrueaboutjoiningtablesthroughanequijoin?（）A、Youcanjoinamaximumoftwotablesthroughanequijoin.B、Youcanjoinamaximumoftwocolumnsthroughanequijoin.C、YouspecifyanequijoinconditionintheSELECTorFROMclausesofaSELECTstatement.D、Tojointwotablesthroughanequijoin,thecolumnsinthejoinconditionmustbeprimarykeyandforeignkeycolumns.E、Youcanjoinntables(allhavingsinglecolumnprimarykeys)inaSQLstatementbyspecifyingaminimumofn-1joinconditions.32.Which command is used to open the database after an incomplete recovery？（）A、 alter database openB、 alter database open repairlogC、 alter database open resetlogsD、 alter database open resetlogE、 alter database resetlogs open33.In which three cases does a checkpoint occur？ （）A、Every three minutes.B、When a log switch occurs.C、When forces by an administrator.D、When a tablespace is taken offline normal.E、When the redo buffer is one-third full.34.Your database is open and the LISTENER listener is running. The new DBA of the system stops thelistener by using the command：  LSNRCTL> STOP  What happens to the sessions that are presently connected to the database instance（）A、The sessions are able to perform only queries.B、The sessions are not affected and continue to function normally.C、The sessions are terminated and the active transactions are rolled back.D、The sessions are not allowed to perform any operations till the listener is started.35.程序全局区（PGA）由哪几个部分组成？各部分存放信息的类型是什么？36.Thedatabaseiscurrentlyopenandthetemp03.dbftempfilebelongingtothedefaulttemporarytablespaceTEMPhasbeencorrupted.Whatstepsshouldyoutaketorecoverfromthistempfilelossinanefficientmanner?（）A、Allowthedatabasetocontinuerunning,droptheTEMPtablespace,andthenre-createitwithnewtempfilesB、Shutdownthedatabase,restoreandrecoverthetempfilefrombackup,andthenopenthedatabasewithRESETLOGSC、Allowthedatabasetocontinuerunning,taketheTEMPtablespaceoffline,dropthemissingtempfile,andthencreateanewtempfileD、Allowthedatabasetocontinuerunning,addanewtempfiletoTEMPtablespacewithanewname,anddropthetempfilethathasbeencorrupted.37.A customer wants to improve the availability of a web application and provide more predictable scalability when scaling out the application.    Which Feature of WebLogic should you recommend to help solve this problem?（）A、Oracle Web GridB、ActiveCacheC、Coherence Grid EditionD、WebLogic Session ReplicationE、Coherence Web Edition38.WhichthreearepropertiesoftheMyISAMstorageengine?（）A、TransactionsupportB、FULLTEXTindexingfortextmatchingC、TableandpagelevellockingsupportD、ForeignkeysupportE、GeospatialindexingF、HASHindexsupportG、Tablelevellockingonly39.Given： 12.String csv = "Sue，5，true，3"； 13.Scanner scanner = new Scanner（ csv ）； 14.scanner.useDelimiter（"，"）；15. int age = scanner.nextInt（）； What is the result？（）A、Compilation fails.B、After line 15， the value of age is 5.C、After line 15， the value of age is 3.D、An exception is thrown at runtime.40.You lost a temporary file that belongs to the default temporary tablespace in your database. From the options provided， which approach would you take to solve the problem？ （）A、flash back the databaseB、import the temporary tablespace from the last exportC、restore all the data files and temporary files from the last full database backup and perform a recoveryD、not perform a recovery， but create a new temporary tablespace， make it the default temporary tablespace and then drop the old tablespace41.Whichtwostatementsaboutsubqueriesaretrue?（）A、Asinglerowsubquerycanretrievedatafromonlyonetable.B、ASQLquerystatementcannotdisplaydatafromtableBthatisreferredtoinitssubquery,unlesstableBisincludedinthemainquery'sFROMclause.C、ASQLquerystatementcandisplaydatafromtableBthatisreferredtoinitssubquery,withoutincludingBinitsownFROMclause.D、Asinglerowsubquerycanretrievedatafrommorethanonetable.E、AsinglerowsubquerycannotbeusedinaconditionwheretheLIKEoperatorisusedforcomparison.F、Amultiple-rowsubquerycannotbeusedinanINSERTstatementtoinsertmultiplerowsatatime.42.A JavaBeans component has the following field：   11. private boolean enabled；   Which two pairs of method declarations follow the JavaBeans standard for accessing this field？（） A、AB、BC、CD、D43.WhichDBMS_SCHEDULERprocedure(s)canbeusedtoalteranexistingjob?（）A、SET_ATTRIBUTE_NULLB、ALTER_JOBC、ALTER_JOB_PARAMETERSD、ALTERE、SET_ATTRIBUTE44.What type of backup is stored in a proprietary RMAN format？（）A、 Backup setB、 Image copyC、 Backup sectionD、 Backup group45.Examinethefollowingimpdpcommandtoimportadatabaseoverthenetworkfromapre-12cOracledatabase(source):Whichthreeareprerequisitesforsuccessfulexecutionofthecommand?（）A、TheimportoperationmustbeperformedbyauseronthetargetdatabasewiththeDATAPUMP_IMP_FULL_DATABASErole,andthedatabaselinkmustconnecttoauseronthesourcedatabasewiththeDATAPUMP_EXD_FULL_DATABASErole.B、Alltheuser-definedtablespacesmustbeinread-onlymodeonthesourcedatabase.C、Theexportdumpfilemustbecreatedbeforestartingtheimportonthetargetdatabase.D、Thesourceandtargetdatabasemustberunningonthesameplatformwiththesameendianness.E、Thepathofdatafilesonthetargetdatabasemustbethesameasthatonthesourcedatabase.F、Theimpdpoperationmustbeperformedbythesameuserthatperformedtheexpdpoperation.46.InwhichcasewouldyouuseaFULLOUTERJOIN?（）A、BothtableshaveNULLvalues.B、Youwantallunmatcheddatafromonetable.C、Youwantallmatcheddatafrombothtables.D、Youwantallunmatcheddatafrombothtables.E、Oneofthetableshasmoredatathantheother.F、Youwantallmatchedandunmatcheddatafromonlyonetable.47.ConsidertheMySQLEnterpriseAuditplugin,Youaddthefollowinglinestothefconfigurationtile:[mysqld]Plugin-load=audit_log.soAudit-log=FORCE_PLUS_PERMANENTYouattempttostartuptheMySQLserviceandnoticethatitfailstostart. Whichtwostatementswouldexplainwhytheservicedidnotstart?（）A、FORCE_PLUS_PERMANENTisnotvalidfortheaudit-logoptionB、Theaudit_log.solibrarydoesnotexistC、Theaudit_log.solibraryisinalocationthatisdifferentfromthatdefinedbytheplugin_diroptionD、TheauditpluginmustbeloadeddynamicallybyusingtheINSTALLPLUGINcommandE、TheauditlogfiledoesnotexistinwhichtowriteauditeventsF、Theaudit_log.solibraryisnotanexecutablefile48.TheEMPtablecontainsthesecolumns: EMPLOYEE_IDNUMBER(4) EMPNAMEVARCHAR2(25) SALARYNUMBER(9,2) HIRE_DATEDATE YouquerythedatabasewiththisSQLstatement: SELECTempname,hire_dateHIREDATE,salary FROMEMP ORDERBYhire_date; Howwilltheresultsbesorted?（）A、randomlyB、ascendingbydateC、descendingbydateD、ascendingalphabeticallyE、descendingalphabetically49.ExaminethestructureoftheEMPLOYEEStable: EMPLOYEE_IDNUMBERNOTNULL,PrimaryKey EMP_NAMEVARCHAR2(30) JOB_IDNUMBER SALNUMBER MGR_IDNUMBERReferencesEMPLOYEE_IDcolumn DEPARTMENT_IDNUMBERForeignkeytoDEPARTMENT_IDcolumnoftheDEPARTMENTStable YoucreatedasequencecalledEMP_ID_SEQinordertopopulatesequentialvaluesfortheEMPLOYEE_IDcolumnoftheEMPLOYEEStable. WhichtwostatementsregardingtheEMP_ID_SEQsequencearetrue?（）A、YoucannotusetheEMP_ID_SEQsequencetopopulatetheJOB_IDcolumn.B、TheEMP_ID_SEQsequenceisinvalidatedwhenyoumodifytheEMPLOYEE_IDcolumn.C、TheEMP_ID_SEQsequenceisnotaffectedbymodificationstotheEMPLOYEEStable.D、AnyothercolumnofNUMBERdatatypeinyourschemacanusetheEMP_ID_SEQsequence.E、TheEMP_ID_SEQsequenceisdroppedautomaticallywhenyoudroptheEMPLOYEEStable.F、TheEMP_ID_SEQsequenceisdroppedautomaticallywhenyoudroptheEMPLOYEE_IDcolumn.50.The backup retention policy is configured as RECOVERY WINDOW 2. You executed the following command in Recovery Manager （RMAN） against your database： RMAN> REPORT OBSOLETE； What would you see in the output？（）A、 a list of all those files that have been deleted in the last two daysB、 a list of all those files that have been recovered within the last two daysC、 a list of all the expired backups and copiesD、 a list of backups and copies that are outside the range covered by the current retention policy51.Whichtwostatementsaboutviewsaretrue?（）A、Aviewcanbecreatedasreadonly.B、Aviewcanbecreatedasajoinontwoormoretables.C、AviewcannothaveanORDERBYclauseintheSELECTstatement.D、AviewcannotbecreatedwithaGROUPBYclauseintheSELECTstatement.E、AviewmusthavealiasesdefinedforthecolumnnamesintheSELECTstatement.52.Consider the following command to create a tablespace in your production database （which is using an Automatic Storage Management [ASM] instance to manage the database files）：  CREATE TABLESPACE user_tbsp  DATAFILE ’+dgroup3（user_temp）/user_files/user_tbsp’ SIZE 200M；  What would be the result of this command？（）A、It would result in an error because the template cannot be used along with the disk group.B、It would result in an error because the path cannot be specified while creating a tablespace in a disk group.C、It would create a tablespace with a data file that has an alias， and its attributes are set by the user-defined template.D、It would create a tablespace with a data file that does not have an alias， and its attributes are set by the user-defined template.53.After performing a clean shut down of the database instance for maintenance， you mount thedatabase and then execute a command to open the database： SQL> ALTER DATABASE OPEN；  Which two statements are true（）A、The online redo log files and online data files are opened.B、All the online data file headers are checked for consistency.C、Instance recovery is performed before opening the database.D、The path and existence of all the log file members are checked54.Whichtwostatementsdescribethebehavioroftheserver'sSQLmode?（）A、Theserver'sSQLmodedetermineshowtheservershouldbehavewhenperformingdatavalidationcheckandinterpretingdifferentformsofsyntaxB、Theserver'sSQLmodedetermineswhethertheservershouldberead-onlyorshouldacceptcommandssuchasINSERTandUPDATEC、Theserver'sSQLmodecanbechangedatthesessionlevelwithaSETSESSIONsql_mode="new_value"commandD、Theserver'sSQLmode,whengloballysetonaslaveserver,appliestoeventssentfromthemaster55.数据字典信息被存放在哪类文件中（）A、数据文件B、控制文件C、重做日志文件D、归档日志文件E、初始化参考文件56.Examine the following statement that is used to modify the constraint on the SALES table： SQL> ALTER TABLE SALES MODIFY CONSTRAINT pk DISABLE VALIDATE； Which three statements are true regarding the above command（）A、The constraint remains valid.B、The index on the constraint is dropped.C、It allows the loading of data into the table using SQL*Loader.D、New data conforms to the constraint， but existing data is not checkedE、It allows the data manipulation on the table using INSERT/UPDATE/DELETE SQL statements.57.The Database Resource Manager is automatically enabled in the maintenance window that runs the Automated Maintenance Task. What is the reason for this？（）  A、 to prevent the creation of an excessive number of scheduler job classesB、 to allow the Automated Maintenance Tasks to use system resources without any restrictionC、 to allow resource sharing only among the Automated Maintenance Tasks in the maintenance windowD、 to prevent the Automated Maintenance Tasks from consuming excessive amounts of system resources58.You find that the execution time of reports in your datawarehouse application is significantly high. You suspect the lack of indexes to be the reason for the degradation in performance.  Which advisory component would you refer to， in order to determine the appropriate indexes？（） A、Memory AdvisorB、Segment AdvisorC、SQL Access AdvisorD、Automatic Workload Repository （AWR）E、Automatic Database Diagnostic Monitor （ADDM）59.Which statement most accurately describes the implementation of a SQL Access Advisor recommendation？（）  A、 SQL Access Advisor recommendations are automatically implemented.B、 Individual SQL Access Advisor recommendations can be scheduled for implementation.C、 All SQL Access Advisor recommendations for a specific task must be implemented at the same time.D、 SQL Access Advisor recommendations are automatically scheduled for implementation during themaintenance window.E、 None of the above.60.BeforeaFlashbackTableoperation,youexecutethefollowingcommand: ALTERTABLEemployeesENABLEROWMOVEMENT; Whywouldyouneedthistobeexecuted?（）A、BecauserowIDsmaychangeduringtheflashbackoperationB、BecausetheobjectnumberchangesaftertheflashbackoperationC、BecausetherowsareretrievedfromtherecyclebinduringtheflashbackoperationD、Becausethetableismovedforwardandbacktoatemporaryduringtheflashbackopertion61.Whichtwoareattributesof/SQL*Plus?（）A、/SQL*Pluscommandscannotbeabbreviated.B、/SQL*Pluscommandsareaccessesfromabrowser.C、/SQL*Pluscommandsareusedtomanipulatedataintables.D、/SQL*Pluscommandsmanipulatetabledefinitionsinthedatabase.E、/SQL*PlusistheOracleproprietaryinterfaceforexecutingSQLstatements.62.ABCCorp.hasconfigured11iOracleApplicationsfortheEnglishlanguage.ItisnowplanningtocommenceoperationsinFranceandsowantsthesameinstancetobeavailableinFrenchaswell.Itcanaccomplishthistaskbyusing（）.A、OracleConfiguratorB、OracleGeneralLedgerC、ApplicationObjectLibraryD、OracleHumanResources63.You executed the following code：   SQL> CERATE TABLE COUNTRY   （COUNTRY_ID CHAR（2） CONSTRAINT COUNTRY_ID_nn NOT NULL，   COUNTRY_NAME VARCHAR2（20），   CURRENCY_NAME VARCHAR2（20），   CONSTRAINT COUNTRY_ID_PK PRIMARY KEY （COUNTRY_ID））   ORGANIZATION INDEX；   Which types of tables will be created automatically？（）A、 journal tableB、 clustered tableC、 mapping tableD、 partitioned table64.YouaremanaginganOracleDatabase11gdatabase.YouwanttotakeabackupontapedrivesoftheUSERStablespacethathasasingledatafileof900MB.Youhavetapedrivesof300MBeach.Toaccomplishthebackup,youissuedthefollowingRMANcommand: RMAN>BACKUP SECTIONSIZE300MTABLESPACEusers; Identifytheappropriateconfigurationtoaccomplishfasterandoptimizedbackupsusingtheabovecommand.（）A、TheSBTchannelmustbeconfigured,withtheMAXPIECESIZEsetto300mb.B、TheSBTchannelmustbeconfigured,withtheparallelismsettingfortheSBTdevicessetto3.C、TheCOMPATIBLEinitializationparameterforthedatabaseinstancemustbesettoatleast10.0.D、TheSBTchannelmustbeconfigured,witht