数据库de管理

Chapter6DataManagement數據管理DatamustbecarefullycontrolbecauseTogetaccurateandmeaningfulresultToprotectthecomputerhardwarefrombeingdamagedSourcesoferror(錯誤來源)Fillinerror(填寫錯誤)Transcriptionerror(抄寫錯誤)Inputerror(輸入錯誤)Howtocontrol?Dataverification(數據核對)Datavalidation(數據驗證)Dataverification(數據核對)DisplaydatatolettheusercheckagainandaskforconfirmDoublecheckTriplecheck…….Forexample:BillPaymentSystem,TicketBookingSystemDatavalidation(數據驗證)ProgrammerforeseepossibleerrorsanddetectthemandprobablycorrectthemPresencecheck-Thisfieldmustbefilled?Rangecheck-Dataexceedalimit?Typecheck-Datatypematchornot?Consistencycheck-Strangedataappear?Controltotal-totalno.ofrecordcorrect?Datavalidation(數據驗證)CheckdigitCanbefoundinIDcard,barcodes,ISBN…UseformulatocheckthedataiscorrectornotForexample:thisstudentID1234(0)c