03Data-Warehousing-and-OPPT课件下载推荐.ppt

03Data-Warehousing-and-OPPT课件下载推荐.ppt

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ConceptsandTechniques,2,October6,2022,DataMining:

ConceptsandTechniques,3,Chapter3:

DataWarehousingandOLAPTechnology:

AnOverview,Whatisadatawarehouse?

Amulti-dimensionaldatamodelDatawarehousearchitectureDatawarehouseimplementationFromdatawarehousingtodatamining,October6,2022,DataMining:

ConceptsandTechniques,4,WhatisDataWarehouse?

Definedinmanydifferentways,butnotrigorously.AdecisionsupportdatabasethatismaintainedseparatelyfromtheorganizationsoperationaldatabaseSupportinformationprocessingbyprovidingasolidplatformofconsolidated,historicaldataforanalysis.“Adatawarehouseisasubject-oriented,integrated,time-variant,andnonvolatilecollectionofdatainsupportofmanagementsdecision-makingprocess.”W.H.InmonDatawarehousing:

Theprocessofconstructingandusingdatawarehouses,October6,2022,DataMining:

ConceptsandTechniques,5,DataWarehouseSubject-Oriented,Organizedaroundmajorsubjects,suchascustomer,product,salesFocusingonthemodelingandanalysisofdatafordecisionmakers,notondailyoperationsortransactionprocessingProvideasimpleandconciseviewaroundparticularsubjectissuesbyexcludingdatathatarenotusefulinthedecisionsupportprocess,October6,2022,DataMining:

ConceptsandTechniques,6,DataWarehouseIntegrated,Constructedbyintegratingmultiple,heterogeneousdatasourcesrelationaldatabases,flatfiles,on-linetransactionrecordsDatacleaninganddataintegrationtechniquesareapplied.Ensureconsistencyinnamingconventions,encodingstructures,attributemeasures,etc.amongdifferentdatasourcesE.g.,Hotelprice:

currency,tax,breakfastcovered,etc.Whendataismovedtothewarehouse,itisconverted.,October6,2022,DataMining:

ConceptsandTechniques,7,DataWarehouseTimeVariant,ThetimehorizonforthedatawarehouseissignificantlylongerthanthatofoperationalsystemsOperationaldatabase:

currentvaluedataDatawarehousedata:

provideinformationfromahistoricalperspective（e.g.,past5-10years）EverykeystructureinthedatawarehouseContainsanelementoftime,explicitlyorimplicitlyButthekeyofoperationaldatamayormaynotcontain“timeelement”,October6,2022,DataMining:

ConceptsandTechniques,8,DataWarehouseNonvolatile,AphysicallyseparatestoreofdatatransformedfromtheoperationalenvironmentOperationalupdateofdatadoesnotoccurinthedatawarehouseenvironmentDoesnotrequiretransactionprocessing,recovery,andconcurrencycontrolmechanismsRequiresonlytwooperationsindataaccessing:

initialloadingofdataandaccessofdata,October6,2022,DataMining:

ConceptsandTechniques,9,DataWarehousevs.HeterogeneousDBMS,TraditionalheterogeneousDBintegration:

AquerydrivenapproachBuildwrappers/mediatorsontopofheterogeneousdatabasesWhenaqueryisposedtoaclientsite,ameta-dictionaryisusedtotranslatethequeryintoqueriesappropriateforindividualheterogeneoussitesinvolved,andtheresultsareintegratedintoaglobalanswersetComplexinformationfiltering,competeforresourcesDatawarehouse:

update-driven,highperformanceInformationfromheterogeneoussourcesisintegratedinadvanceandstoredinwarehousesfordirectqueryandanalysis,October6,2022,DataMining:

ConceptsandTechniques,10,DataWarehousevs.OperationalDBMS,OLTP（on-linetransactionprocessing）MajortaskoftraditionalrelationalDBMSDay-to-dayoperations:

purchasing,inventory,banking,manufacturing,payroll,registration,accounting,etc.OLAP（on-lineanalyticalprocessing）MajortaskofdatawarehousesystemDataanalysisanddecisionmakingDistinctfeatures（OLTPvs.OLAP）:

Userandsystemorientation:

customervs.marketDatacontents:

current,detailedvs.historical,consolidatedDatabasedesign:

ER+applicationvs.star+subjectView:

current,localvs.evolutionary,integratedAccesspatterns:

updatevs.read-onlybutcomplexqueries,October6,2022,DataMining:

ConceptsandTechniques,11,OLTPvs.OLAP,October6,2022,DataMining:

ConceptsandTechniques,12,WhySeparateDataWarehouse?

HighperformanceforbothsystemsDBMStunedforOLTP:

accessmethods,indexing,concurrencycontrol,recoveryWarehousetunedforOLAP:

complexOLAPqueries,multidimensionalview,consolidationDifferentfunctionsanddifferentdata:

missingdata:

DecisionsupportrequireshistoricaldatawhichoperationalDBsdonottypicallymaintaindataconsolidation:

DSrequiresconsolidation（aggregation,summarization）ofdatafromheterogeneoussourcesdataquality:

differentsourcestypicallyuseinconsistentdatarepresentations,codesandformatswhichhavetobereconciledNote:

TherearemoreandmoresystemswhichperformOLAPanalysisdirectlyonrelationaldatabases,October6,2022,DataMi