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1、東南大學(xué)博士學(xué)位論文數(shù)據(jù)倉庫物化視圖在線算法研究姓名:張柏禮申請學(xué)位級別:博士專業(yè):計算機(jī)應(yīng)用技術(shù)指導(dǎo)教師:孫志揮20050701AbstractAdatewarehouseisadatarepository,whichcollectsandmaintainsalargemountofdatafrommullipledism'buted,autonomousandpossiblyheterogeneousdatasoIM.Oftenthedataisstoredintheformofmaterializedview3forthepurposeefficientlyimpl
2、ementingdccision-suppo仳orOLAPqueries.Firstly,theselectionofviewsformaterializationisoneofthemostissuesinthedesigndatewarehouse,it’sgoalistoselect∞appropriatesetofviewsthatminimizestotalqueryresponsetimeand/orthecostofmaintainingtheselectedviews,givonalimitedamountofrasonsce,e.g.,storagesp
3、ace,materializationtime,ortotalviewmaIntanancetime.Secondly,maintaininglotsofmaterializedviewsischallenging.especiallyffthedatasources2reautonomousandviewsofthedataatthedatawarehousespanmultiplesoume“q.Theviewshavetobemaintainedintimetoreflecttheupdatesdoneagainstthebaserelationsstoredatt
4、hevariousdatesources.n圮e伍cientmaintenanceofmaterializedviewshasbecomeanotherimportantresearchiss∞.Theusualmethodsis廿扭tthematerializedviewsaraselectedandmaintainedoffline。forexample,thestaticselectionalgorithmofviewisemployedtogenerateorregeneratethematerializedviewset,andbatchupdatepolicy
5、isusedtomaintainthematnight,However,wheremtheamountofdataenteringawerchousc,thequeryloads,andtheneedtoobtain叩-to-dateresponsesareauincreasing,the‘'night"’timeavailableformakingthewarehouseup-to-dateisshrinking.Theseu'andsnecessitateefficientonlinealgorithmsformaterializedviews.Inthispaper
6、,itisemphasizedtomakedeeperresearchontheselectionalgorithmsandmaintenancealgorithmsofmaterializedviewsduringthedatawarehouseon-line.Themaincontributionsofthisdissertationareasfollows:(1)Tosolvetheshortageofthestaticselectionalgorithmofmaterializedview,thepaperpresentsPMVS.preprocessorofma
7、terializedviewselectionapproach.PMVSmakesu∞ofthequerysparsenessanddatasparsenassinmulti-dimensionaldatasets,andreducesthetimecomplex(searchspacc)ofthestaticselectionalgorithm,Sothecostofstaticalgorithmsonspaceandtimecanbecutdowntofitforonlinedemand.(2)Preseataimprov