SSD7數(shù)據(jù)庫(kù)系統(tǒng)選擇題答案

Multiple-ChoiceQuiz11.AnE-Commercesystemconsistsofthefollowingcomponents.Whichofthesesamecomponentsmustbeincludedinadatabase?(c)Thedata,suchasinformationaboutthegoodsavailableforsale,customers,ordersplaced,shippinginformation,etc.Adatabasemustincludeacollectionofprogramsthatcontrolthedata,suchasprogramstocreate,maintain,andmanipulatethedata.Theseprogramscanbeeasilyusedtocreate,maintain,andmanipulatedatainotherdomains.Adatabasemustincludeacollectionofprogramsthatoperateonthedata,butarespecifictotheE-commercesystem.Theseprogramsenableuserstobrowsethroughthestore-items,placeorders,trackshipping,etc.(a)I,II,andIII(b)IandIIonly(c)Ionly(d)IIonly2.AnE-Commercedatabasecontainsdataaboutcustomers,products,orders,systemresponsetimes,etc.WhichofthefollowingcanbespecifiedasintegrityconstraintsinanE-Commercedatabasesystem?(d)NotwoproductscanhavethesameproductID.TheDBMSresponsetimeforallWebrequestsshouldbeatmost2seconds.Acustomerordercannothavemorethanoneshippingaddress.(a)Ionly(b)I,II,andIII(c)IandIIonly(d)IandIIIonlyFeedback:TheconstraintsI,IIandIIIspecifytheapplicationsemanticsofthedatacapturedintheE-Commercedatabase.ConstraintIII,althoughitseemscontrarytocommonsense,isnotsomethingthatcanbeprohibitedbytheDBMSbecausetheDBMSisgeneralpurpose.TheresponsetimeoftheDBMScannotbeenforcedbytheDBMS.Itdependsonfactorssuchtheprocessorspeed,memoryavailable,etc.3.AnE-Commercesystemconsistsofthefollowingcomponents.Whichofthesesamecomponentswillconstituteadatabasesystem?(d)Thedata,suchasinformationaboutthegoodsavailableforsale,customers,ordersplaced,shippinginformation,etc.Acollectionofprogramsthatcontrolthedata,suchasprogramstocreate,maintain,andmanipulatethedataconstitutesadatabasesystem.Theseprogramscanbeeasilyusedtocreate,maintain,andmanipulatedatainotherdomainssuchasinalibraryinformationsystem.Acollectionofprogramsthatoperateonthedata,butarespecifictotheE-commercesystem,constitutesadatabasesystem.Theseprogramsenableuserstobrowsethroughthestore-items,placeorders,trackshipping,etc.(a)IandIIonly(b)IIonly(c)Ionly(d)I,II,andIIIFeedback:Adatabasesystemincludesthedata,theDBMS,andtheapplication-specificprogramsthatoperateonthatdata.5.Inadatabasesystem,whoseresponsibilityisittoprovidedataconsistency?(d)(a)thedatabaseadministrator's(b)theuser's(c)theapplicationprogrammer's(d)theDBMS's6.Adatabaseisneededforwhichofthefollowingapplicationscenarios?(b)Avideostorethatneedstokeeptrackofdataaboutmembers,aboutvideoscarriedbythestore,aboutvideosrentedbymembers,aswellasdataconcerningborrow-date,return-date,andpaymentinformation.Inthehumanresourcesdepartmentofacompany,informationaboutemployees,theirtitles,theirsalariesandsickdays,andaboutvacationdaystakenbyeachemployee.Acomputer-simulatedvideogamewhichneedstocalculateanddisplay,thephysical(x,y)locationofeachactorinthegame,thespeedwithwhichtheyaremovingatthecurrentinstant,thedirectioninwhichtheyaremoving,theactiontheyareperforming,theangleatwhichthegame-playerisviewingthescene.(a)IandIIIonly(b)IandIIonly(c)I,II,andIII(d)Ionly7.Thephysicalstoragestructurewillbe_____totheapplicationprogrammerinadatabaseapproach,andwillbe_____totheapplicationprogrammerinafilesystemapproach.(b)(a)visible,visible(b)hidden,visible(c)visible,hidden(d)hidden,hiddenMultiple-ChoiceQuiz21.TheforeignkeyinatableT1_____thesame_____asthecorrespondingprimarykeyintableT2.(d)musthave,nameneednothave,namemusthave,domain(a)I,II,andIII(b)IandII(c)IandIII(d)IIandIII2.Thedegreeofatableisthenumberof_____inthetable.(c)(a)keys(b)rows(c)columns(d)foreignkeys3.Thearityofatableisthenumberof_____inthetable.(c)(a)rows(b)foreignkeys(c)columns(d)keys4.Thecardinalityofatableisthenumberof_____inthetable.(b)(a)keys(b)rows(c)columns(d)foreignkeys5.WhichofthefollowingSQLstatementscanbeusedtoaddarowtoatable?(c)(a)CREATE(b)ADD(c)INSERT(d)APPEND6.TheSQLclausetoperformasetUNIONoperationis(b)(a)UNITE(b)UNION(c)COMBINE(d)MELD7.TheSQLclausetoperformasetdifferenceoperationis(b)(a)OMIT(b)EXCEPT(c)REJECT(d)DIFFER8.DDLisusedto(c)(a)addcontentstotables.(b)definethestructureofdatabaseapplications.(c)specifythestructureofadatabase.(d)accessthecontentsoftables.9.Adeletionoperationwill_____ifthedeletionleadstotheviolationofareferentialintegrityconstraint.(a)(a)fail(b)crashthesystem(c)succeedwithwarning(d)succeedwithoutwarning10.Thetermquerybyexamplerefersto(b)(a)aqueryforSQLexamples(b)avisualquerylanguagedevelopedbyIBM(c)exampleSQLqueriesprovidedbyotherusersthatcanbemodifiedtosuitcurrentneeds(d)exampleSQLqueriesprovidedbytheDBMSthatuserscanmodifytosuittheircurrentneeds11.Whatinformationisnecessarywhenspecifyingthestructureofatable?(d)(a)thenameofthetableandtheamountofstoragespacetobeallocatedtothetable(b)thenameofthetableandthenamesofthetable'sattributes(c)thenameofthetable,thenamesofthetable'sattributes,thedatatypesofthetable'sattributes,theformatsofthetable'sattributes,andthemaximumnumberofrowsthatthetablecanhave(d)thenameofthetable,thenamesofthetable'sattributes,thedatatypesofattributes,andtheformatsofattributes12.WhatcanbespecifiedintheselectionconditionofaSELECTstatement?(a)(a)aBooleanoperation(b)theconditionsunderwhichthestatementshouldbeexecuted(c)thetimeatwhichtheselectionshouldbeperformed(d)anarithmeticoperation13.WhichofthefollowingSQLstatementscanbeusedtomodifyjustonerow(outofmanyrows)inatable?(c)(a)ALTER(b)MODIFY(c)UPDATE(d)CHANGE14.Adeletionoperationwill_____ifthedeletionleadstotheviolationofareferentialintegrityconstraint.(c)(a)succeedwithwarning(b)succeedwithoutwarning(c)fail(d)crashthesystem15.WhichofthefollowingSQLstatementscanbeusedtocreatearelationaltable?(b)(a)APPEND(b)CREATE(c)ADD(d)INSERT16.WithQueryByExample,auserentersaqueryby(b)(a)typingasyntacticallycorrectSQLquerythatusescolumnandtablenamessimilartothecorrectcolumnandtablenamesinadatabase(b)fillinginskeletontablesofthedatabasewithexamplesofwhatistoberetrieved(c)placingSQLkeywords,suchasselect,underthecolumnnamestheywanttoretrieve(d)writinganEnglishdescriptionofthedatathattheuserneeds17.DMLisusedto(d)(a)manipulatethestructureofdatabaseapplications.(b)specifythestructureofadatabase.(c)addanddeletetables.(d)add/modify/deletedatainthedatabase.18.Ajoinoperationjoins_____tablesinto_____.(a)(a)two,one(b)three,two(c)four,two(d)three,one//union/intersect/except參加運(yùn)算的關(guān)系必須相容（即含有相同的屬性集）19.Adifferenceoperationcanbeappliedtotablesthat(b)(a)havethesamecolumnnames(b)areunioncompatible(c)arethesamesize(d)havethesamename20.WhichofthefollowingSQLstatementscanbeusedtoremovearowfromatable?(c)(a)REMOVE(b)ERASE(c)DELETE(d)DESTROYMultiple-ChoiceQuiz31.InSQL,onefunctionoftheASoperatoristo(c)(a)controltheorderinwhichaquery’srowsaresorted(b)definethedomainofanattribute(c)customizethenamesofcolumnsinaquery’sresult(d)limitthecardinalityofarelation2.Whenremovingatablefromtheschema,usingtheRESTRICToptionwould(a)(a)removethetableiftherearenoreferencestoit(b)removethetableandallothertablesthatthespecifiedtablerefersto(c)removethetableandallreferencestoit(d)recursivelyremovethetableandallothertablesthattheremovedtablerefersto3.InSQL,adatabasecanbedestroyedbywhichofthefollowing?(a)(a)thecommandDROPSCHEMA(b)thecommandDELETEDATABASE(c)thecommandDESTROYDATABASE(d)aseriesofDESTROYTABLEcommands4.WhenastringwhoselengthisstrictlylessthannisenteredasthevalueofafieldwhoseSQLdatatypeisVARCHAR(n),thesystemrespondsby(b)(a)re-promptingfortheentryofastringwhoselengthisexactlyn.(b)storingthestringasis.(c)paddingtheendofthestringwithNULLcharacterstolengthnbeforestoringit.(d)paddingtheendofthestringwithspacestolengthnbeforestoringit.5.InSQL,whendestroyingadatabase,theRESTRICToptionremoves(b)(a)everythinginthespecifieddatabase:thedata,schema,etc.(b)theschemaifthedatabasehasnodata(emptytables)(c)thedataandschemafromthespecifieddatabase,butnotfromrelateddatabases(d)thedatabutnottheschema6.InSQL,adatabasecanbecreatedbywhichofthefollowing?(d)(a)aseriesofCREATETABLEcommands(b)thecommandADDDATABASE(c)thecommandINSERTDATABASE(d)thecommandCREATESCHEMA7.InaFROMclauseofaSELECTstatementinSQL,atablecanbealiasedwithwhichofthefollowingoperators?(b)(a)ALIAS(b)AS(c)RENAME(d)@8.InSQL,whichofthefollowingclausescanbeusedtosortresultsinascendingordescendingorderofattributevalues?(c)(a)SORT(b)GROUPBY(c)ORDERBY(d)ARRANGEBY9.WhenspecifyingaselectioncriterioninSQL,attributescanberenamedwithwhichofthefollowingoperators?(d)(a)ALIAS(b)@(c)RENAME(d)AS10.InSQL,whichofthefollowingoperatorscanbeusedtoexpresssearchesthattestforarangeinaselectioncondition?(a)(a)BETWEEN(b)RANGE(c)STARTandEND(d)FROMandTOMultiple-ChoiceQuiz41.Whichofthefollowingistrueaboutupdateabilityofviews?(a)(a)Aviewisupdateableifitinvolvesonetableandcontainsakey.(b)Aviewisupdateableifitinvolvesmultipletablesandnokeys.(c)Aviewisupdateableifitinvolvesonetableanddoesnotcontainakey.(d)Aviewisnotupdateableunderanycircumstance.2.Averticalviewallowsusersaccessto(d)(a)onlythesystemtables(b)onlyspecificrowsofthedefiningtables(c)onlytheusertables(d)onlyspecificcolumnsofthedefiningtables3.Ahorizontalviewallowsusersaccessto(a)(a)onlyspecificrowsofthedefiningtables(b)onlyspecificcolumnsofthedefiningtables(c)onlythesystemtables(d)onlythebasetables4.Considertwotables,Employee(EmpNo,Name,DeptNo)andDepartment(DeptNo,Name,Manager)withprimarykeysbeingEmpNoandDeptNorespectively.TheDeptNoattributeoftheEmployeetablehasaNOTNULLconstraintandisaforeignkeythatreferencestheDeptNoattributeoftheDepartmenttable.TheManagerattributeoftheDepartmenttablehasaNOTNULLconstraintandisaforeignkeythatreferencestheEmpNoattributeoftheEmployeetable.Whenthetablesareempty,theonlywaytoinsertrowsintothetwotablesis(d)(a)touseatransactioninNOTDEFERRABLEmode(b)touseatransactioneitherinDEFERRABLEmodeorinNOTDEFERRABLEmode(c)nottouseatransactionatall(d)touseatransactioninDEFERRABLEmode5.TheSQLkeyword_____makesthemodificationsofthetransactionpermanent,whiletheSQLkeyword_____discardsthemodificationsofthetransaction.(b)(a)WRITE,ABORT(b)COMMIT,ROLLBACK(c)UPDATE,SELECT(d)SAVE,CANCEL6.Whichofthefollowingcommandscanbeusedtogiveaccesspermissionstoatable?(a)(a)GRANT(b)AUTHORIZE(c)PERMIT(d)ALLOW7.Whocanalwaysgiveaccesspermissionstoatable?(b)(a)onlythesuper-user(b)theownerofthetable(c)theuserofthetable(d)onlythedatabaseadministrator(DBA)8.Whichofthefollowingcommandscanbeusedtoremoveaccessprivilegesassociatedwithatable?(a)(a)REVOKE(b)DENY(c)RETRACT(d)REMOVE9.WhenisembeddedSQLreferredtoasstaticSQL?(d)(a)whentheSQLstatementscanneverbechanged(b)whentheembeddedSQLoperatesonthestaticpartofthedatabase(c)whentheembeddedSQLalwaysreturnsthesamesetofresults(d)whentheembeddedSQListranslatedintoDBMScallsatcompile-time10.WhenisembeddedSQLreferredtoasdynamicSQL?(a)(a)whentheembeddedSQListranslatedintoDBMScallsatrun-time(b)whentheembeddedSQLoperatesonthedynamicpartofthedatabase(c)whentheembeddedSQLalwaysreturnsdifferentsetsofresults(d)whentheSQLstatementsarechangedineveryrun11.Whichofthefollowingistrueaboutviewsbeinguptodate?(a)(a)Viewsarealwaysuptodate.(b)Viewscanbeautomaticallymadeuptodateperiodicallybythesystem.(c)Viewsareneveruptodate;thereisalwaysalagtime.(d)Viewsareuptodateonlyafterthesynchronizationoperationbytheuser.12.WhichofthefollowingreferentiallytriggeredactionsaresupportedinSQLwhenareferentialintegrityconstraintisviolated?(a)SETNULLREJECTCASCADESETDEFAULT(a)I,III,andIVonly(b)IIandIIIonly(c)IandIVonly(d)I,II,andIIIonly13.Whichofthefollowingistrueaboutupdateabilityofviews?(c)(a)Aviewisnotupdateableifitinvolvesonetableandcontainsakey.(b)Aviewisupdateableunderallcircumstances.(c)Aviewisnotupdateableifitinvolvesaggregatefunctionsandnestedqueries.(d)Aviewisnotupdateableunderanycircumstance.Multiple-ChoiceQuiz51.InanERmodel,whatisarecursiverelationshiptype?(d)(a)Thetypeofrelationshipthatdoesnotbelonganywhere(b)Anever-endingtypeofrelationship(c)Therelationshiptypewheretherelatedentitiesareoneandthesame(d)Thetypeofrelationshipbetweenentitiesofoneentitytype2.InanERmodel,thecardinalityratioofarelationshiptypeis(b)(a)thenumberofinstancesofrelationshipsofthatrelationshiptype(b)thenumberofrelationshipsofthatrelationshiptypeinwhichanentitycanparticipate(c)theminimumnumberofentitiesthatcanparticipateinthatrelationshiptype(d)thenumberofentitytypesinvolvedinthatrelationshiptype3.Whichofthefollowingistrueaboutstorageforderivedattributes?(b)(a)Derivedattributesmustnotbestored.(b)Derivedattributesareusuallynotstoredbecausetheycanbecomputed.(c)Derivedattributesmustbestored.(d)Derivedattributesareusuallystoredbecausestorageimprovesretrievalperformance.4.Aweakentitytypeimpliesa(c)(a)relationshipwithpartialparticipationconstraint(b)strongrelationshiptype(c)relationshipwithtotalparticipationconstraint(d)weakrelationshiptype5.IntheEntity-Relationshipmodel,propertiesthatcharacterizeentitiesandrelationshipsaremodeledas(c)(a)weakentities(b)entitytypes(c)attributes(d)participationconstraints6.IntheEntity-Relationshipmodel,aderivedattributeisone(c)(a)thatiscomposedofmultipleatomicattributes(b)thatmayhavemultiplevaluessimultaneously(c)whosevaluecanbecomputedfromthevaluesofotherattributes(d)thatcharacterizesarelationshipinsteadofanentity7.InanERmodel,whichofthefollowingistrueaboutacomponentattribute?(b)(a)Acomponentattributealwayscontainsothercomponents.(b)Acomponentattributecanbeacompositeattribute.(c)Acomponentattributeisalwaysatomic.(d)Componentattributesmustalwaysbecombinedbyanaggregationoperation.8.InERmodeling,generalizationistheprocessofgenerating(b)(a)entitiesoutofattributes(b)superclassesoutofsubclasses(c)subclassesoutofsuperclasses(d)attributesoutofentities9.Whichofthefollowingistrueaboutattributesinarelationalmodel?(d)Attributescanbemulti-valued.Attributescanbecomposite.(a)IIonly(b)NeitherInorII(c)Ionly(d)BothIandII10.WhenmappingfromanERmodeltoarelationalmodel,astrongentityismappedintoa(d)(a)row(b)column(c)key(d)table11.IntheEntity-Relationshipmodel,thedegreeofarelationshipspecifieswhichofthefollowing?(d)(a)Thecardinalityratiooftherelationship(b)Thenumberofattributesthatcharacterizetherelationship(c)Thenumberofintegrityconstraintsrequiredtoimplementtherelationship(d)Thenumberofentitiesthatparticipateintherelationship12.WhatisanidentifyingownerinanERmodel?(b)(a)Theentityuponwhichastrongentity'sexistencedepends(b)Theentityuponwhichaweakentity'sexistencedepends(c)Therelationshipthatidentifiesastrongentity'sowner(d)Therelationshipthatidentifiesaweakentity'sownerMultiple-ChoiceQuiz61.Whichofthefollowingisaproperty(areproperties)exhibitedbygoodrelationalschemas?Theuseofnullvaluesintuples(d)ThegroupingofasmanyattributesaspossibleintoonemaintableTheeliminationofdataredundancytoavoidupdateanomalies(a)IIandIIIonly(b)None(c)IandIIonly(d)IIIonly2.Throughnormalization,updateanomalies(c)(a)isusuallyleftunchanged(b)canbeminimizedbutnoteliminated(c)canbeeliminated(d)canbemaximized3.Considerthefollowingfunctionaldependency.{A,B}->{C}Regardingthisdependency,whichofthefollowingstatementsis(are)true?(c)ThevaluesofCareuniquelydeterminedbythevaluesofA.ThevaluesofAareuniquelydeterminedbythevaluesofC.(a)IandII(b)Ionly(c)None(d)IIonly4.Whichofthefollowingproblemscanbecausedbydataredundancyinarelationalschema?Inefficientuseofspace(a)UpdateanomaliesandpossiblelossofdataInefficientuseofprocessingtime(a)I,II,andIII(b)IandIIonly(c)IIonly(d)IandIIIonly5.Throughnormalization,dataredundancy(d)(a)canbeminimizedbutnoteliminated(b)areusuallyleftunchanged(c)canbemaximized(d)canbeeliminated6.ConsideratablewithatomicattributesA,B,andCandthefollowingfunctionaldependencies.A->BB->CIftheprimarykeyofthistableisattributeA,thenthisrelationsatisfieswhichofthefollowingnormalforms?(c)FirstSecondThird(a)I,IIandIII(b)Ionly(c)IandIIonly(d)None7.Forarelationtobein3NF,itshouldnotcontain_____attributethatistransitivelydependenton_____.(a)(a)anon-primarykey,theprimarykey(b)aprimarykey,anon-primarykey(c)aprimarykey,aforeignkey(d)anon-primarykey,aforeignkey8.TheFDX->YisafulldependencyinarelationR,ifthereis_____attributeAthatcanbe_____Xandthedependencystillholds.(d)(a)atleastone,removedfrom(b)atleastone,addedto(c)no,addedto(d)no,removedfrom9.Forarelationtobein2NF,_____attributemustbefullyfunctionallydependenton_____.(b)(a)everyalternatekey,theprimarykey(b)everynon-primary-key,theprimarykey(c)everynon-key,atleastonekey(d)everynon-key,everykey10.TheFDX->YisapartialdependencyinarelationR,ifthereis_____attributeAthatcanbe_____Xandthedependencystillholds.(c)(a)atleastone,addedto(b)no,removedfrom(c)atleastone,removedfrom(d)no,addedto11.Whichofthefollowingstatementsconcerningnormalformsistrue?(b)(a)Thelowerthenormalformnumber,thebettertheschemadesignis.(b)Arelationthatisinsecondnormalformisalsoinfirstnormalform.(c)Schemasthatareinsecondnormalformareconsideredthebest.(d)Eachnormalformcontainsastateofindependentproperties,unrelatedtoothernormalforms.Multiple-ChoiceQuiz71.Allchangesmadebyacommittedtransactioncanberecovered(d)(a)onlyiftherehavebeennosoftwarefailures(b)onlyiftherehavebeennohardwarefailures(c)onlyiftherehavebeennosoftwareANDnohardwarefailures(d)irrespectiveofwhethertherehavebeenhardwareorsoftwarefailures2.Isitpossibleforavalidtransactiontoseethemodified,yetuncommitteddataofanothervalidtransactionwhentheisolationlevelissettoSERIALIZABLE?(a)(a)Itisnotpossibleforatransactiontoseethemodified,yetuncommitted,dataofanothertransaction,evenifbothtransactionsareworkingonthesamedata,andevenifbothtransactionsareconcurrent.(b)Itispossibleforatransactiontoseethemodified,yetuncommitted,dataofanothertransactionevenifbothtransactionsarenotworkingonthesamedata,ANDevenifbothtransactionsareNOTconcurrent.(c)Itispossibleforatransactiontoseethemodified,yetuncommitted,dataofanothertransactiononlyifbothtransactionsworkonthesamedata,ANDbothtransactionsareNOTconcurrent.(d)Itispossibleforatransactiontoseethemodified,yetuncommitted,dataofanothertransaction,onlyifbothtransactionsworkonthesamedata,ANDbothtransactionsareconcurrent.3.Alivelockoccurswhen(a)(a)atransactionisabortedandrestartedrepeatedly(b)atransactionholdingalockisaborted(c)2ormoretransactionswaitindefinitelybecauseeachholdsthedataitemsofanother(d)anabortedtransactionholdingalockisrestarted4.Inatwo-phaselockingprotocol,whathappensduringthegrowingphase?(d)(a)Thetransactioncanacquirelocks,andcanreleaseitslocks.(b)Thetransactioncannotacquirelocks,butcanreleaseitslocks.(c)Thetransactioncanacquirelocks,andcanreleaseitslocksaslongasthenumberofacquiredlocksisgreaterthanthenumberofreleasedlocks.(d)Thetransactioncanacquirelocks,butcannotreleaseitslocks.5.Anexclusivelockonadataitemrepresentspermissiontoperformwhichoftheoperations,readandwrite,onthedataitem?(c)(a)Readonly(b)Neitherreadnorwrite(c)Bothreadandwrite(d)Writeonly6.Inatwo-phaselockingprotocol,whathappensduringtheshrinkingphase?(a)(a)Thetransactioncannotacquirelocks,butcanreleaseitslocks.(b)Thetransactioncanacquirelocks,butcannotreleaseitslocks.(c)Thetransactioncanacquirelocks,andcanreleaseitslocks.(d)Thetransactioncanacquirelocks,andcanreleaseitslocksaslongasthenumberofreleasedlocksisgreaterthanthenumberofacquiredlocks.7.Thestricttwo-phaselockingprotocolis_____toimplement.(c)(a)easierthanmosttwo-phaselockingprotocols(b)moredifficultthanmosttwo-phaselockingprotocols(c)theeasiesttwo-phaselockingprotocol(d)themostdifficulttwo-phaselockingprotocol8.Forcepropagationpolicy_____redoactions,andno-forcepropagationpolicy_____redoactions.(a)(a)doesnotrequire,requires(b)requires,requires(c)requires,doesnotrequire(d)doesnotrequire,doesnotrequire9.Immediateupdatepolicy_____undoactions,anddeferredupdatepolicy_____undoactions.(c)(a)doesnotrequire,requires(b)doesnotrequire,doesnotrequire(c)requires,doesnotrequire(d)requires,requires10.Duringrecovery,inwhichofthefollowingwaysarethebeforeandafterimagesusedbytheundoandredoactions?(d)undoactionusesthebeforeimageundoactionusestheafterimageredoactionusestheafterimageredoactionusesthebeforeimage(a)I,II,andIIIonly(b)I,III,andIVonly(c)I,II,III,andIV(d)IandIIIonlyMultiple-ChoiceQuiz81.Whichofthefollowingarepropertiesofagoodhashfunction?(c)Itshouldbecomputedefficiently.Itshouldminimizethenumberofcollisionsbyspreadingkeysasevenlyanduniformlyaspossible.ItshouldalwaysusetheModulo(MOD)function.(a)Ionly(b)IIIonly(c)IandIIonly(d)IIonly2.Wheredoheapfilesaddnewrecords?(c)(a)atrandomlocationsintheheapfile(b)inthemiddleoftheheapfile(c)attheendoftheheapfile(d)atthebeginningoftheheapfile3.Hashingexhibitsthebestperformancefor(a)rangequeries(b)orderingqueryresultsbasedonthekeyusedforhashing(c)equalitysearchesinvolvingthekey,providedthekeyisusedforhashing(d)sequentialscanoftheentiretable4.Asparseindexcontainsentriesfor(a)(a)somerecordsofatable(b)somefieldsofatable(c)allfieldsofatable(d)allrecordsofatable5.Aprimaryindex_____definedonakeyfield,andasecondaryindex_____definedonakeyfield.(d)(a)neednotbe,shouldnotbe(b)shouldbe,shouldnotbe(c)neednotbe,neednotbe(d)shouldbe,neednotbe6.Eachindexentryinanindexfilecontains(c)anindexingvalueapointertothepagewheretherecordwiththevalueappearsanindexingfunction(a)Ionly(b)I,II,andIII(c)IandIIonly(d)IIIonly7.Acylinderofamulti-platterharddiskconsistsof(b)(a)theoutermosttrack(b)trackswiththesamediameter(c)theinnermosttrack(d)trackswithdifferentdiameters8.Toimprovetheperformanceofadatabase,(d)(a)neverusebufferingwhentransferringdatabetweensecondarystorageandmainmemory(b)neverusehashfileswhendecidingonanappropriateindexingstructure(c)alwaysusehashfileswhendecidingonanappropriateindexingstructure(d)minimizetheamountofdatatransferredbetweensecondarystorageandmainmemory9.Thetermblocktransfertimereferstotheamountoftimeittakesto(c)(a)loadtheaddressofadiskblockfromanindex(b)movetheread/writeheadtotheappropriatetrackonthedisk(c)readdatafromadisk(d)positiontheappropriatediskblockundertheread/writehead10.Thetermblockingfactorreferstothenumberof(c)(a)diskblocksthatformatrack(b)diskblocksthatareonaharddiskdriveplatter(c)databaserecordsthatcanbestoredonadiskblock(d)cylindersonaharddiskdrive11.Howdoeschainedoverflowsolvetheproblemofcollisionsinhashing?(d)(a)Thefirstavailableemptybucketinachainedlistofbucketsisused.(b)Thefirstavailableslotintheoverflowareawhereslotsarechainedusingahashfunctionisused.(c)Thefirstavailableslotinalinkedlistofslotsthatisconnec