数据库基于值的查询优化的研究与实践

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1、大连理工大学硕士学位论文数据库基于值的查询优化的研究与实践姓名：孟凡辉申请学位级别：硕士专业：计算机应用技术指导教师：王秀坤20050316数据库基于值的查询优化的研究与实践TheResearchandApplicationofDatabaseValue-basedQueryOptimizationAbstractQueryoptimizationisallimportanttechniquefordesigningandimplementingdatabasesystem．Itisacrucialfactorthataffectsthecapabilityofdatabase．T11

2、egreatsuccessofrelationaldatabaseandSQLmainlybenefitsfromthedevelopmentofqueryoptimizationtechnology．Searchinganoptimizedexecutivestrategyforeverycomplexqueryisthekeyofsuccessfordatabasedevelopment．Indatabasefield，itisstillanN·Pproblem．Intheprocessofquery,ineffectiveSQL，shortageofstatisticsandin

3、correctjoinorderareallthereasonsforloweringthequeryrate．Basedonthestatisticsdictionaryandthemodel，thevalue-basedqueryoptimizationistorewritetheineffectiveSQLandselectthebestjoinorderformulti—tables．AccordingtothefactualproblemofqueryefficiencyinChineseCognitiveDatabaseandHeilongjiangDecision-mak

4、ingandSupportingSystem，thispaperanalyzesdetailedlytheconcretelyexecutiveprocessofSQLstatementreferencetothecharacteristicofdatabasequery．Searchingtheapproachofimprovingthequeryefficiencyinmassdataqueryandthecreationofdata—warehouse，thereareseveralschemes，suchas“automatingstatisticsmanagementforq

5、ueryoptimizers'’，“rewritingtheSQLstatementbased0nstaffsties”．Atthesametime，thispaperisnotlimitedinaprojectandwillapplytheseschemestothesimilardatabasemodel．Inthisfoundation，ParticleSwarm0ptimization(PS0)，anewevolutivecomputemodelisintroducedtoqueryoptimizationtoconstructaparticleswarlTlmodelinth

6、estatespaceofquerystrategy,andtooptimizethejoinoperationsusingPSO．Experimentsindicatethatthenewmethodisbetterthantraditionalmethodsinsearchingthebestexecutivestrategy．Finally,combiningtheoryandpractices，itisdemonstratedthattheoptimizedstrategyaboveisappliedtopracticalprojects，“ChineseCognitiveDa

7、tabaseManagementSystem’’and“HeilongjiangDecision-makingmadSupportingSystem'’．Ithasimprovedusers’queryefficiencyindeed．KeyWords：QueryOptimization；DatabaseStatistics；QueryRewriting；ParticleSwarmAlgorithm；QueryStrategy．Ⅱ．独创性说明作