嵌入式移動(dòng)實(shí)時(shí)數(shù)據(jù)庫(kù)中一種基于代價(jià)模型的查詢優(yōu)化技術(shù).pdf

1、華中科技大學(xué)碩士學(xué)位論文嵌入式移動(dòng)實(shí)時(shí)數(shù)據(jù)庫(kù)中一種基于代價(jià)模型的查詢優(yōu)化技術(shù)姓名：周偉芳申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：計(jì)算機(jī)軟件與理論指導(dǎo)教師：盧炎生20070602IIAbstractWiththecuttingedgetechnologyadvanceinwirelessmobilecomputersthequeryprocessinginamobileenvironmentinvolvesjoinprocessingamongdiffe

2、rentsiteswhichincludestaticserversmobilecomputers.Becauseoftheneedfenergysavingalsothepresenceofasymmetricfeaturesinamobilecomputingenvironmenttheconventionalqueryprocessingfadistributeddatabasecannotbedirectlyappliedtoa

3、mobilecomputingsystem.theregularoptimizationalgithmsofdistributedquerysuchastheoptimizationalgithmbasedonjointheoptimizationalgithmbasedonsemijoinSDD1algithmhavebeengreatlyresearchedwidlyusedinDDBMS.MobileDBMSisonekindof

4、DDBMSwhichsupptsmobilecomputing.HowevertheregularoptimizationalgithmsusedinDDBMSmustbedevelopedsoastoappletotheMobileDBMS.withoutdoinganychangesthesealgithmswon’tbefittedfthemobilecomputingenvironment.Therearemanyasymmet

5、ricfeaturesinamobileenvironment.Theninlightofthesefeaturesqueryprocessingmethodsfbothjoinqueryprocessingcanbedevised.Intuitivelyemployingsemijoinoperationsinamobilecomputingenvironmentisabletofurtherreduceboththeamountof

6、datatransmissionenergyconsumption.Accdingtothoseasymmetricfeaturesofamobilecomputingsystemtwodifferentjoinmethodshavebeenexamined.Fqueryprocessingwhichreferstotheprocessingofmultijoinqueriestwoqueryprocessingschemesarede

7、vised.Itisshownbythesimulationresultsthatbyexploitingtheasymmetricfeaturestheseacteristicfunctionsareverypowerfulinreducingboththeamountsofenergyconsumptiondatatransmissionincurredcanleadtothedesignofanefficienteffective