武汉理工大学数据库系统原理总复习题完整版含答案.docx
《武汉理工大学数据库系统原理总复习题完整版含答案.docx》由会员分享,可在线阅读,更多相关《武汉理工大学数据库系统原理总复习题完整版含答案.docx(32页珍藏版)》请在冰豆网上搜索。
武汉理工大学数据库系统原理总复习题完整版含答案
武汉理工大学数据库系统原理总复习题(完整版含答案)
1.Questions
1.1Whatisthepurposeofadatabase?
ANSWER:
Thepurposeofadatabaseistohelppeopletrackofthings.
1.2Whatisthemostcommonlyusedtypeofdatabase?
ANSWER:
themostcommonlyusedtypeofdatabaseistherelationaldatabase.
1.7Definethetermsdataandinformation.Explainhowthetwotermsdiffer.
ANSWER:
Dataarerecordedfactsandnumbers.
wecannowdefineinformationas:
●Knowledgederivedfromdata.
●Datapresentedinameaningfulcontext.
●Dataprocessedbysumming,ordering,averaging,grouping,comparingorothersimilaroperations.
1.10Whatproblemcanoccurwhenadatabaseisprocessedbymorethanoneuser?
ANSWER:
Whenmorethanoneuseremploysadatabaseapplication,theseisalwaysthechancethatoneuser'sworkmayinterferewithother's.
1.12Whatisthepurposeofthelargestdatabasesate-commercecompaniessuchasA?
ANSWER:
Thelargestdatabasesarethosethattrackcustomerbrowserbehavior.(用来记录用户的浏览行为的。
)
1.13Howdothee-commercecompaniesusethesedatabases?
.
ANSWER:
E-commercecompaniesuseWebactivitydatabasestodeterminewhichitemsonaWebpagearepopularandsuccessfulandwhicharenot.
1.14Howdodigitaldashboardanddataminingapplicationsdifferfromtransactionprocessingapplications?
ANSWER:
Digitaldashboardsandotherreportingsystemsassesspastandcurrentperformance.Dataminingapplicationspredictfutureperformance.
1.15Explainwhyasmalldatabaseisnotnecessarilysimplerthanalargeone.
Whatarethefunctionsofapplicationprograms?
ANSWER:
Supposedwehave2companywhicharedifferentinsalesbuthavesimilardatabase.Thoughthedifferenceinsale,bothhavethesamekindsofdata,aboutthesamenumberoftablesofdata,andthesamelevelofcomplexityindatarelationships.Onlytheamountofdatavariesfromonetotheother.Thus,althoughadatabaseforasmallbusinessmaybesmall,itisnotnecessarilysimple.
1.18WhatisStructuredQueryLanguage(SQL),andwhyisitimportant?
ANSWER:
StructuredQueryLanguage(SQL)isaninternationallyrecognizedstandardlanguage.BecauseitcanbeunderstoodbyallcommercialDBMSproducts,indatabaseprocessingandthefactthatdatabaseapplicationstypicallysendSQLstatementstotheDBMSforprocessing.
1.19WhatdoesDBMSstandfor?
ANSWER:
Thedatabasemanagementsystem.
1.20WhatarethefunctionsoftheDBMS?
ANSWER:
Itcanbeusedtocreate,process,andadministerthedatabase.
1.21NamethreevendorsofDBMSproducts.
ANSWER:
IBM,Microsoft,Oracle.
1.22Definethetermdatabase.
ANSWER:
Adatabaseisaself-describingcollectionofintegratedtables.
1.23Whyisadatabaseconsideredtobeself-describing?
ANSWER:
Adatabaseisself-describingbecauseitcontainsadescriptionofitself.Thus,databasescontainnotonlytablesofuserdata,butalsotablesofdatathatdescribethatuserdata.
1.24Whatismetadata?
Howdoesthistermpertaintoadatabase?
ANSWER:
databasescontainnotonlytablesofuserdata,butalsotablesofdatathatdescribethatuserdata.Suchdescriptivedataiscalledmetadatabecauseitisdataaboutdata.
1.25Whatadvantageisthereinstoringmetadataintables?
ANSWER:
Becausemetadataisstoredintables,youcanuseSQLtoqueryit.Thus,bylearninghowtowriteSQLtoqueryusertables,youwillalsolearnhowtowriteSQLtoquerymetadata.
1.26Listthecomponentsofadatabaseotherthanusertablesandmetadata.
•Tablesofuserdata
•Metadata
•Indexes
•Storedprocedures
•Triggers
•Securitydata
•Backup/recoverydata
1.27IsMicrosoftAccessaDBMS?
Whyorwhynot?
ANSWER:
No,MicrosoftAccessisnotjustaDBMS.Rather,itisapersonaldatabasesystem:
aDBMSplusanapplicationgenerator.
BecausealthoughMicrosoftAccesscontainsaDBMSenginethatcreates,processes,andadministersthedatabase,italsocontainsform,report,andquerycomponentsthataretheMicrosoftAccessapplicationgenerator
1.37Listseveralconsequencesofapoorlydesigneddatabase.
ANSWER:
-TheymayrequireapplicationdeveloperstowriteoverlycomplexandcontrivedSQLtoget–wanteddata.
-theymaybedifficulttoadapttonewandchangingrequirements.
-theymayfailinsomeotherway.
1.38Explaintwowaysthatadatabasecanbedesignedfromexistingdata.
ANSWER:
ThefirsttypeofdatabasedesigninvolvesdatabasesthatareconstructedfromexistingData.
Asecondwaythatdatabasesaredesignedisforthedevelopmentofnewinformationsystems.
1.39Whatisadatawarehouse?
Whatisadatamart?
ANSWER:
Thedatawarehouseanddatamartdatabasesstoredataspecificallyorganizedforresearchandreportingpurposes,andthesedataoftenareexportedtootheranalyticaltools,suchasSAS’sEnterpriseMiner,IBM'sSPSSDataModeler,orTIBCO'sSpotfireMetrics.
1.40Describethegeneralprocessofdesigningadatabaseforanewinformationsystem.
ANSWER:
First,theteamcreatesadatamodelfromtherequirementsstatementsandthentransformsthatdatamodelintoadatabasedesign.
1.41Explaintwowaysthatdatabasescanberedesigned.
ANSWER:
Inthefirst,adatabaseisadaptedtoneworchangingrequirements.Thisprocesssometimesiscalleddatabasemigration.Inthemigrationprocess,tablesmaybecreated,modified,orremoved;relationshipsmaybealtered;dataconstraintsmaybechanged;andsoforth.
Thesecondtypeofdatabaseredesigninvolvestheintegrationoftwoormoredatabases.Thistypeofredesigniscommonwhenadaptingorremovinglegacysystems.Itisalsocommonforenterpriseapplicationintegration,whentwoormorepreviouslyseparateinformationsystemsareadaptedtoworkwitheachother.
1.42Whatdoesthetermdatabasemigrationmean?
ANSWER:
Theprocessofadatabaseisadaptedtoneworchangingrequirements.
1.43Summarizethevariouswaysthatyoumightworkwithdatabasetechnology.
ANSWER:
Inourcareer,wemayworkwithdatabasetechnologyaseitherauserorasadatabaseadministrator.
Asauser,youmaybeaknowledgeworkerwhopreparesreports,minesdata,anddoesothertypesofdataanalysisoryoumaybeaprogrammerwhowritesapplicationsthatprocessthedatabase.
Alternatively,youmightbeadatabaseadministratorwhodesigns,constructs,andmanagesthedatabaseitself.UsersareprimarilyconcernedwithconstructingSQLstatementstogetandputthedatatheywant.Databaseadministratorsareprimarilyconcernedwiththemanagementofthedatabase.
1.44Whatjobfunctionsdoesaknowledgeworkerperform?
ANSWER:
preparingreports,miningdata,anddoingothertypesofdataanalysis.
1.45Whatjobfunctionsdoesadatabaseadministratorperform?
ANSWER:
designing,constructing,andmanagingthedatabaseitself.
1.47Whatneeddrovethedevelopmentofthefirstdatabasetechnology?
ANSWER:
Theneedfordataintegrationdrovethedevelopmentofthefirstdatabasetechnology.
1.48WhatareDataLanguage/IandCODASYLDBTG?
ANSWER:
DataLanguage/I(DL/I)usedhierarchiesortrees(seeAppendixG)torepresentrelationships.
Thissubcommitteedevelopedastandarddatamodelthatcametobearitsname—theCODASYLDBTGmodel.Itwasanunnecessarilycomplicatedmodel.Thisdatarelationshipuseddatastructurescallednetworks.
1.49WhowasE.F.Codd?
ANSWER:
E.F.Coddwasalittle-knownIBMengineerpublishedapaperintheCommunicationsoftheACM3inwhichheappliedtheconceptsofabranchofmathematicscalledrelationalalgebratotheproblemof“shareddatabanks,”asdatabaseswerethenknown.Theresultsofthisworkarenowtherelationalmodelfordatabases,andallrelationaldatabaseDBMSproductsarebuiltonthismodel.
1.50Whatweretheearlyobjectionstotherelationalmodel?
1.51NametwoearlyrelationalDBMSproducts.
ANSWER:
OracleDatabase,DB2.
1.52WhataresomeofthereasonsforthesuccessofOracleDatabase?
ANSWER:
1,itwouldrunonjustaboutanycomputerandjustaboutanyoperatingsystem.
2,OracleDatabasehad,andcontinuestohave,anelegantandefficientinternaldesign.
1.53NamethreeearlypersonalcomputerDBMSproducts.
ANSWER:
dBase,R:
base,Paradox.
1.55WhatwasthepurposeofOODBMSproducts?
StatetworeasonsthatOODBMSproductswerenotsuccessful.
ANSWER:
TheyweredesignedtomakeiteasytostorethedataencapsulatedinOOPobjects.
Thereweretworeasonsfortheirlackofacceptance.First,usinganOODBMSrequiredthattherelationaldatabeconvertedfromrelationalformattoobject-orientedformat.BythetimeOODBMSemerged,billionsuponbillionsofbytesofdatawerestoredinrelationalformatinorganizationaldatabases.NocompanywaswillingtoundergotheexpensivetravailofconvertingthosedatabasestobeabletousethenewOODBMS.
Second,object-orienteddatabaseshadnosubstantialadvantageoverrelationaldatabasesformostcommercialdatabaseprocessing.Asyouwillseeinthenextchapter,SQLisnotobjectoriented.Butitworks,andthousandsofdevelopershavecreatedprogramsthatuseit.Withoutademonstrableadvantageoverrelationaldatabases,noorganizationwaswillingtotakeonthetaskofconvertingtheirdatatoOODBMSformat.
1.56WhatcharacteristicofHTTPwasaproblemfordatabaseprocessingapplications?
ANSWER:
HTTPisastatelessprotocol;aserverreceivesarequestfromauser,processestherequest,andthenforgetsabouttheuserandtherequest.Manydatabaseinteractionsaremultistage.Acustomerviewsproducts,addsoneormoretoashoppingcart,viewsmoreproducts,addsmoretotheshoppingcart,andeventuallychecksout.Astatelessprotocolcannotbeusedforsuchapplications.
1.57WhatisanopensourceDBMSproduct?
WhichofthefiveDBMSproduc