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1、第-15-页共15页databaseDatabaseisinaccordancewiththedatastructuretoorganize,storageandmanagementofdatawarehouse,whicharisesfromfiftyyearsago,withthedatingofinformationtechnologyandthedevelopmentofthemarket,especiallysincethe1990s,datamanagementisnolongermerelydatastorageandma
2、nagement,andtransformedintouserneedsofthevariousdatamanagementway.Thedatabasehasavarietyoftypes,fromthemostsimplestoragehavevariousdataformtocanbecarriedoutmassdatastorageoflargedatabasesystemsareobtainedineachaspecthasextensiveapplication.ThebirthofdatamanagementDatabas
3、e'shistorycanbetracedbacktofiftyyearsago,whenthedatamanagementisverysimple.Throughalotofclassification,comparisonandformrenderingmachinerunningmillionsofpunchedCARDSfordataprocessing,itsoperationresultsonpaperprintedorpunchedcardmadenew.Whilethedatamanagementispunchedcar
4、dforallthesephysicalstorageandhandling.However,1951yearRemingtonRandcorporation(RemingtonRandInc.)anenzymecalledUnivacIcomputerlaunchedaasecondcaninputhundredsofrecordingtapedrives,whichhascauseddatamanagementrevolution.1956IBMproducethefirstdiskdrives--theRAMACModel305.
5、Thisdriveshave50blanks,eachblanksdiameteris2feet,canstore5MBofdata.Thebiggestadvantageisusediskcanberandomlyaccessdata,andpunchedCARDSandtapecanorderaccessdata.Databasesystemappearsinthe1960sthebud.Whencomputerbegantowidelyusedindatamanagement,thesharingofdataputforwardm
6、oreandmorehighdemand.Thetraditionalfilesystemalreadycannotsatisfypeople'sneeds.Manageandsharedatacanunifythedatabasemanagementsystem(DBMS)cameintobeing.Thedatamodelisthecoreandfoundationofdatabasesystem,variousDBMSsoftwarearebasedonadatamodel.Sousuallyinaccordancewiththe
7、characteristicsofthedatamodelandthetraditionaldatabasesystemintomeshdatabase,thehierarchydatabaseandrelationaldatabasethreetypes.Structuredquerylanguage(SQL)1第-15-页共15页commercialdatabasesystemsrequireaquerylanguagethatismoreuserfriendly.Inthischapter,westudySQL,themostin
8、fluentialcommerciallymarketedquerylanguage,SQL.SQLusesacombinationofrelational-algebraandrelational-calc
