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附录1英文资料IMPROVINGADONETPERFORMANCEIMPROVINGNETAPPLICATIONPERFORMANCEANDSCALABILITYSUMMARYTHISCHAPTERPROVIDESPROVENSTRATEGIESTOHELPYOUDESIGNANDDEVELOPSCALABLEDATAACCESSSOLUTIONSTOPICSCOVEREDINCLUDEDIFFERENTTECHNIQUESTOPASSDATAACROSSAPPLICATIONLAYERS,MANAGINGTHEDATABASECONNECTIONPOOL,OPTIMIZINGSTOREDPROCEDURECALLS,REDUCINGDATASETSERIALIZATIONCOST,TECHNIQUESFORPAGINGTHROUGHLARGERESULTSETS,MANAGINGTRANSACTIONS,HANDLINGBLOBS,ANDMUCHMOREOBJECTIVESOPTIMIZEYOURDATAACCESSDESIGNCHOOSEBETWEENDATASETSANDDATAREADERSRUNEFFICIENTDATABASECOMMANDSPASSDATABETWEENLAYERSEFFICIENTLYPERFORMEFFICIENTTRANSACTIONSOPTIMIZECONNECTIONMANAGEMENTEVALUATETHECOSTOFPAGINGTHROUGHRECORDSEVALUATECRITERIAFORANALYZINGDATAACCESSPERFORMANCEAPPLYPERFORMANCECONSIDERATIONSTOBINARYLARGEOBJECTBLOBMANIPULATIONOVERVIEWWELLDESIGNEDDATAACCESSCODEANDDATAPROCESSINGCOMMANDSAREESSENTIALELEMENTSFORAPPLICATIONPERFORMANCEANDSCALABILITYTYPICALLY,THEDATABASEISAFOCALPOINTFORAPPLICATIONLOADBECAUSETHEMAJORITYOFAPPLICATIONREQUESTSREQUIREDATATHATCOMESFROMADATABASETHISCHAPTERPROVIDESPROVENSTRATEGIESFORDESIGNINGANDIMPLEMENTINGDATAACCESSCODEFORPERFORMANCEANDSCALABILITYHOWTOUSETHISCHAPTERUSETHISCHAPTERTOIMPROVETHEIMPLEMENTATIONOFYOURDATAACCESSCODEFORPERFORMANCEANDSCALABILITYTOGETTHEMOSTOUTOFTHISCHAPTER,CONSIDERTHEFOLLOWINGJUMPTOTOPICSORREADBEGINNINGTOENDTHEMAINHEADINGSINTHISCHAPTERHELPYOUTOQUICKLYIDENTIFYANDTHENLOCATETHETOPICTHATINTERESTSYOUALTERNATIVELY,YOUCANREADTHECHAPTERBEGINNINGTOENDTOGAINATHOROUGHAPPRECIATIONOFTHEISSUESTHATAFFECTADONETPERFORMANCEUSETHECHECKLISTUSECHECKLISTADONETPERFORMANCEINTHECHECKLISTSSECTIONOFTHISGUIDETOQUICKLYVIEWANDEVALUATETHEGUIDELINESPRESENTEDINTHISCHAPTERUSETHEARCHITECTURESECTIONOFTHISCHAPTERTOUNDERSTANDHOWADONETWORKSBYUNDERSTANDINGTHEARCHITECTURE,YOUCANMAKEBETTERDESIGNANDIMPLEMENTATIONCHOICESUNDERSTANDCOREADONETCOMPONENTS,SUCHASDATAPROVIDEROBJECTSANDTHEDATASETOBJECTUSETHEDESIGNCONSIDERATIONSSECTIONOFTHISCHAPTERTOUNDERSTANDTHEHIGHLEVELDECISIONSTHATWILLAFFECTIMPLEMENTATIONCHOICESFORADONETCODEMEASUREYOURAPPLICATIONPERFORMANCELEARNABOUTTHEKEYMETRICSTHATYOUCANUSETOMEASUREAPPLICATIONPERFORMANCEYOUHAVETOMEASUREAPPLICATIONPERFORMANCESOTHATYOUCANIDENTIFYANDRESOLVEPERFORMANCEISSUESTESTYOURAPPLICATIONPERFORMANCETESTINGNETAPPLICATIONPERFORMANCETOLEARNHOWTOAPPLYPERFORMANCETESTINGTOYOURAPPLICATIONYOUHAVETOAPPLYACOHERENTTESTINGPROCESSANDANALYZETHERESULTSTUNEYOURAPPLICATIONPERFORMANCETUNINGNETAPPLICATIONPERFORMANCETOLEARNHOWTORESOLVEPERFORMANCEISSUESTHATYOUIDENTIFYTHROUGHTHEUSEOFTUNINGMETRICSTUNESQLSERVERREADCHAPTER14,IMPROVINGSQLSERVERPERFORMANCETOENSURETHATYOURMICROSOFTSQLSERVER™DATABASEISAPPROPRIATELYCONFIGUREDARCHITECTUREADONETRELIESONDATAPROVIDERSTOPROVIDEACCESSTOTHEUNDERLYINGDATASOURCEEACHDATAPROVIDEREXPOSESASETOFOBJECTSTHATYOUUSETOMANAGECONNECTIONS,RETRIEVEDATA,ANDUPDATEDATATHECOREOBJECTSARETHEFOLLOWINGCONNECTIONCOMMANDDATAREADERDATAADAPTERINADDITION,ADONETPROVIDESTHEDATASETOBJECT,WHICHPROVIDESADISCONNECTEDCACHEOFDATATHEDATASETOBJECTDOESNOTREQUIREASPECIFICTYPEOFDATASOURCEANDISNOTTIEDTOTHEUNDERLYINGDATASOURCETHATTHEDATAWASOBTAINEDFROMTHEBASICADONETARCHITECTUREISSHOWNINFIGURE121FIGURE121ADONETARCHITECTURETHEFOLLOWINGLISTOUTLINESTHEPURPOSEOFEACHOFTHEMAINADONETOBJECTSCONNECTIONTHISOBJECTREPRESENTSACONNECTIONTOADATABASECOMMANDTHISOBJECTREPRESENTSANSQLSTATEMENTTHATISRUNWHILECONNECTEDTOADATASOURCETHISOBJECTCANBEASTOREDPROCEDUREORADIRECTSQLSTATEMENTDATAREADERTHISOBJECTRETRIEVESAREADONLY,FORWARDONLYSTREAMOFDATAFROMADATABASETHEDATAREADEROBJECTISDESIGNEDFORCONNECTEDSCENARIOSANDOFFERSBETTERPERFORMANCETHANREADINGDATAINTOADATASETOBJECTATTHEEXPENSEOFFUNCTIONALITYFORMOREINFORMATIONABOUTHOWTOUSEDATAREADEROBJECTSANDDATASETOBJECTS,SEEDATASETVSDATAREADERLATERINTHISCHAPTERDATAADAPTERTHISOBJECTCHANNELSDATATOANDFROMADATASETOBJECTANDTHEUNDERLYINGDATASOURCETHEDATAADAPTEROBJECTALSOPROVIDESENHANCEDBATCHUPDATEFEATURESTHATWEREPREVIOUSLYASSOCIATEDWITHTHEADORECORDSETOBJECTDATASETTHEDATASETOBJECTREPRESENTSADISCONNECTED,CACHEDSETOFDATATHEDATASETISINDEPENDENTOFTHEPROVIDERANDISNOTTIEDTOTHEUNDERLYINGDATASOURCETHATMIGHTHAVEBEENUSEDTOPOPULATEITDATASETCANEASILYBEPASSEDFROMCOMPONENTTOCOMPONENTTHROUGHTHEVARIOUSLAYERSOFANAPPLICATION,ANDITCANBESERIALIZEDASXMLYOUSHOULDBEAWAREOFTHEWAYADATASETISINTERNALLYCONSTRUCTEDBECAUSETHEDATASETCONTAINSAPOTENTIALLYLARGENUMBEROFINTERNALOBJECTSTHISMEANSTHATALARGENUMBEROFMEMORYALLOCATIONSAREREQUIREDTOCONSTRUCTATYPICALDATASETADATASETCONSISTSOFONEORMOREDATATABLEOBJECTSTOGETHERWITHDATARELATIONOBJECTSTHATMAINTAINTABLERELATIONSHIPINFORMATIONEACHDATATABLECONTAINSDATAROWOBJECTSANDDATACOLUMNOBJECTSCONSTRAINTOBJECTSAREUSEDTOREPRESENTACONSTRAINTTHATCANBEENFORCEDONONEORMOREDATACOLUMNOBJECTSNOTEYOUCANALSOUSETYPEDDATASETSTHATDERIVEFROMTHEBASICDATASETCLASSTYPEDDATASETSPROVIDEBENEFITSATBUILDTIMEANDATRUNTIMEFORMOREINFORMATION,SEETYPEDDATASETSLATERINTHISCHAPTERDATAVIEWALTHOUGHTHEDATAVIEWOBJECTISNOTSHOWNINFIGURE121,YOUCANUSEADATAVIEWTOSORTANDFILTERDATAINADATATABLETHISCAPABILITYISOFTENUSEDFORDATABINDINGABSTRACTINGDATAACCESSADONETISDESIGNEDAROUNDASETOFGENE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