英文文献《对分布式系统数据库的介绍》

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1、AnIntroductiontoDatabaseSystemsADatabaseManagementSystem(DBMS)consistsofacollectionofinterrelateddataandasetofprogramstoaccessthosedata.Adatabaseisacollectionofdataorganizedtoservermanyapplicationsefficientlybycentralizingthedataandminimizingredundantdata.The

2、primarygoeilofaDBMSistoprovideanenvironmentthatisbothconvenientandefficienttouseinretrievingandstoringdatabaseinformation.Databasesystemsaredesignedtomanagelargebodiesofinfonnation.ThemanagementofdatainvoIvesboththedefinitionofstrueturesforthestorageofinforma

3、tionandtheprovisionofmochanismsforthemanipulationofinformationstored,despitesystemmustavoidpossibleanomalousresuIts.Theimportantofinformationinmostorganizations,whichdeterminesthevalueofthedatabase,has1edtothedevelopmentofalargebodyofconceptsandtechniqucsfort

4、hedatabase,hasledtothedevelopmentofalargebodyofconceptsandtechniquesfortheefficientmanagementofdata.Thetypicalfile-processingsystemissupportedbyaconventionaloperatingsystem.Permanentrecordsarestoredinvariousfiles,anddifferentapplicationprogreimsarewrittentoex

5、tractrecordsfrom,andtoaddrecordsto,theappropriatefiles.BeforetheadventofDBMSs,organizationstypicallystoredinformationusingsuchsystems.Keepingorganizationalinformationinafile-processingsystemhasanumberofmajordisadvantages.Dataredundancyandinconsistcncy.Datared

6、undemeyistheprosenccofduplicatedatainmultipiedatafiles.Sincethefilesandapplicationprogramsarecreatedbydifferentprogrammersoveralongperiod,thevariousfilesarelikelytohavedifferentformatsandtheprogramsmaybewritteninseveralprogramminglanguages.Moreover,thesameinf

7、ormationmaybeduplicatedinseveralplaces(files).Thisredundancyleadstohigherstorageandaccesscost.Inaddition,itmayleadtodatainconsistency;thatis,thevariouscopiesofthesamedatamaynolongeragree.Difficultyinaccessingdata.Thepointhereisthatconventiormlfile-processinge

8、nvironmentsdonotallowneededdatatoberetrievedinaconvcnicntandefficientmanner.Moreresponsivedata~rctricvalsystemsmustbedevelopedforgeneraluse.Integrityproblems.Thedatavaluesstoredinthedatab