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1、AdvancedDatabaseManagementSystemsDataStreamManagementAlvaroAAFernandesSchoolofComputerScience,UniversityofManchesterAAAF(SchoolofCS,Manchester)AdvancedDBMSsDecember10,20071/123OutlineDataStreamsDefinedandMotivatedDataStreamsv.StoredDataWindowsonDataStreamsQuerySyntaxandSemanticsinDSMSsAAAF(Sch
2、oolofCS,Manchester)AdvancedDBMSsDecember10,20072/123DataStreamsDefinedandMotivatedDataStreams(1)Whatarethey?IAstreamisacontinuous,potentiallyunbounded,potentiallyvoluminous,real-time,sequenceofdataelements(e.g.,tuples).IOften,aniteminastreamcanbeseenasthenotificationthataneventhasoccurred.ITher
3、etwomajorkindsofsources,viz.:Itransactionalstreams,inwhichcaseanitemconveysanotificationthataninteractionbetweenentitieshastakenplace;Imonitoringstreams,inwhichcaseanitemconveysanotificationthatsomeentityhaschanged(i.e.,thatitsstatehasevolved).AAAF(SchoolofCS,Manchester)AdvancedDBMSsDecember10,
4、20073/123DataStreamsDefinedandMotivatedDataStreams(2)Whydotheymatter?(1)Examplesoftransactionalstreamsinclude:IcreditcardpurchasesbyconsumersfrommerchantsIphonecallsbycallerstodialledpartiesIwebaccessesbyclientofresourcesheldbyserversIinter-organizationalinteractions(e.g.,purchaseofsupplies,de
5、liveryofgood,paymentforservicesprovided,etc.)Iintra-organizationalinteractions(e.g.,movementofpartsfromwarehousestoproductionlines,fromproductionlinestodeliveryvehicles,fromvehiclestoloadingbays,fromloadingbaystoshelves,etc.)AAAF(SchoolofCS,Manchester)AdvancedDBMSsDecember10,20074/123DataStre
6、amsDefinedandMotivatedDataStreams(3)Whydotheymatter?(2)Examplesofmonitoringstreamsinclude:IpricemovementsinfinancialandcommoditymarketsItrafficlevelsinnetworksIphysicalparameters(suchastemperature,pressure,etc.)ofphysicalphenomena(suchasoceans,theatmosphere,etc.)AAAF(SchoolofCS,Manchester)Advance
7、dDBMSsDecember10,20075/123DataStreamsv.StoredDataDataStreamv.DataManagementSystems(1)Contrasts(1)DBMSsDSMSsDataPersistentTransientTupleset/bagTuplesequenceBoundedsizeUnboundedsizeUpdatesExplicitImplicitModifyinplaceAppendonlyAccessRandomSeque
