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1、Chapter2:FundamentalsofDataWarehouse第二章：数据仓库基础1Chapter2:FundamentalsofDataWarehouseDefinitionofdatawarehouseMulti-dimensionaldatamodelEfficientDataCubeComputationandOLAPoperationsSummery2DefinitionofDataWarehouseAdecisionsupportrepository（存储）thatismaintaine
2、dseparatelyfromtheorganization’soperationaldatabaseSupportinformationprocessingbyprovidingasolidplatform(平台)ofsummarized,historicaldataforanalysis.3DefinitionofDataWarehouse“Adatawarehouseisasubject-oriented(面向主题),integrated(集成),time-variant(随时间变化),andnonvo
3、latile(非易失)collectionofdatainsupportofmanagement’sdecision-makingprocess.”—W.H.Inmon4SubjectOrientedIntegratedTimeVariantNonVolatileDataWarehouseFourFeaturesofDataWarehouseDataWarehouse—Subject-OrientedOrganizedaroundmajorsubjects,suchasproduct,sales，etc.Fo
4、cusingonthemodelingandanalysisofdatafordecisionmakers,notondailyoperationsortransactionprocessing.Provideasimpleandconciseviewaroundparticularsubjectissuesbyexcludingdatathatarenotusefulinthedecisionsupportprocess.6OLTPApplicationsCustomer financial informa
5、tionDataWarehouseSubjectEquity PlansSharesInsuranceLoansSavingsSubject-OrientedDataiscategorizedandstoredbybusinesssubjectratherthanbyapplication.DataWarehouse—IntegratedConstructedbyintegratingmultiple,heterogeneousdatasourcesrelationaldatabases,flatfiles,
6、etc.Dataextractionandintegrationtechniquesareapplied.Ensureconsistency(一致性)innamingconventions,structures,attributemeasures,etc.amongdifferentdatasources8DataWarehouseOLTPApplicationsSavingsCurrentaccountsLoansCustomerIntegratedDataWarehouse—TimeVariantThet
7、imehorizonforthedatawarehouseissignificantlylongerthanthatofoperationalsystems.Operationaldatabase:currentdata.Datawarehouse:provideinformationfromahistoricalperspective(e.g.,past5-10years)EverykeystructureinthedatawarehouseContainsanelementoftime,explicitl
8、yorimplicitlyButthekeyofoperationaldatamayormaynotcontain“timeelement”.1001/9702/9703/97JanuaryFebruaryMarchDataWarehouseTimeData199719971997TimeVariant(时变性)Dataisstoredasaseriesofsnapshots,eachreprese
