s)GivenR(A,B,C,D,E,F,G,H),andF={A®F,B®E,BE®F,E®C,A®G,G®CD}holdingonR,findoutallcandidatekeysofR(利用求候选键算法,给出计算过程)Answers:(8points)GivenaschemaR(A,B,C)andF={A→B,B→C}holdsonStudent,position{R1(A,B);R2(A,C)}onR,positionlossyorlossless?Why?positiondependencypreserving?Why?.Answers:(6points)ForthefollowingschemaRandFholdingonit,listallthecandidatekeys,givethehighestnormalformitbelongsto,andexplainwhyR(A,B,C,D,E),F={A®BC,CD®E,B®D,E®A}Answers:(12points)ConsideringtheschemaR=(athlete-id,game-event,grade,categoryofgames,mangerofgames)thatdescribesthesportsmeeting.Itisassumedthatforeachathlete,ifhetakespartinagameevent,ordingtothedescriptionsmentionedabove,listthefunctionaldependencysetFthatholdsonR(3points)ListallthecandidatekeysofR.(2points)Givealosslessanddependency-positionofRinto3NF.(5points)答案:
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