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时间:2019-03-04
《华南农业大学数据库考试答案》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、华南农业大学期末考试试卷(A卷)2015-2016学年第一学期考试科目:数据库系统考试类型:闭卷考试时间:120分钟学号姓名年级专业装题号一二三四五总分得分评阅人订Question1:true-falsequestion(30points)Foreachofthefollowingstatements,indicatewhetheritisTRUEorFALSE(UsingTforTRUE得分andFforFALSE).Youwillget1pointforeachcorrectanswer,and0pointforeachwrongorblankanswer
2、.BESURETOWRITEYOURANSWERINTHEANSWERSHEET!线1.Databasesystemsaredesignedforbothdefiningstoragestructuresandprovidingmechanismsformanipulationofinformation.2.Comparingwithdatabasesystem,file-processingsystemhasmanydisadvantagessuchlikedataredundancyandconsistency,concurrent-accessanoma
3、lies.3.Physicaldataindependenceindatabasemeansthattheuserworkingonthelogicallevelneedknownothingaboutcomplexityofthephysicallevelofdatabase.4.Theoveralldesignofdatabaseisthedatabaseschema,whilecollectionofdatastoredinthedatabaseataparticularmomentisaninstanceofthedatabase.5.TheEntit
4、y-Relationshipdatamodelisoftenusedinlogical1designphase.6.SQLisarelationallanguagethatusedasbothDDLandDML.7.Metadataisdataaboutdatathatarestoredindatadictionary.8.Atupleisalsoknownasacolumnindatabasetable.9.ArelationshipinanERmodelcanhasitsownattributes.10.Compositeattributesarenota
5、llowedinERmodel.11.Theclosureofafunctionaldependencysetincludesallfunctionaldependenciesintheset.12.Dependencypreservationisnecessarytoapracticaldecompositionalgorithm.13.Themostcommontypeofrelationshipencounteredindatamodelingisternaryrelationship.14.ArelationalschemaRisinBCNFifdom
6、ainsofallattributesofRareatomic.15.Atuplevariableisavariablethatstandsforatuple,inotherwords,itisavariablewhosedomainisthesetofalltuples.16.Aforeignkeyofarelationisasetofattributes(oneormore)thatallowustoidentifyatupleinthatrelationuniquely.17.Thesetintersectionoperationcanbereplaci
7、ngbyapairofset-differenceoperations.18.Anyrelationthatisnotpartofthelogicalmodel,butismade2visibletoauserasavirtualrelation,iscalledaview.19.InSQL,theouterjoinoperationdefineshowtuplesineachrelationthatdonotmatchanytupleintheotherrelationare装treated.20.Themaindatabasedesignphaseincl
8、udesrequirementanal
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