半结构化数据到结构化数据的无损映射.pdf

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1、JournaiofSoutheastUniversity（EngiishEdition）Mar.2002Voi.18No.1ISSN1003—7985LosslessMappingfromSemi-StructuredDatatoStructuredData!!!LiWenwuJinYuanpingTongMina（DepartmentofComputerScienceandEngineering，SoutheastUniversity，Nanjing210096，China）Abstract：Mostsemi-structureddataareo

2、fcertainstructurereguiarity.Havingbeenstoredasstructureddatainreiationaidatabase（RDB），theycanbeeffectiveiymanagedbydatabasemanagementsystem（DBMS）.Somesemi-structureddataaredifficuittotransformduetotheirirreguiarstructures.Wedesignanefficientaigorithmanddatastructureforensuring

3、iossiesstransformation.Webringforwardanapproachofschemaextractionthroughdatamining，inwhichdifferentkindsofeiementsaretransformedrespectiveiyandiossiessmappingfromsemi-structureddatatostructureddatacanbeachieved.Keywords：semi-structureddata，DTD，RDB，schemamapping，DOM，overfiowdat

4、aTheWebhasbeenbecominganimportantapproa-usingreiationaiDBMStomanagesemi-structureddatachtoinformationacguiring，transmittingandexchang-andgettheoriginaiDTDwheneveritisneededindataing.TheWebdataareofcertainstructurereguiarity.exchangeprocessing.Butdifferentfromstructureddataintr

5、aditionaidata-ThemappingschememapsDTDdataintothebase，theyarenotinaccordancewithaconcretedatafoiiowingthreereiationaitabies：modei.Theyhavethepropertiesofseif-description，1）Eiementtabie，storeseiementinformationsuchdynamicchangingandsemi-structure.Extensibieasfathereiementname，ei

6、ementtype，eiementreiativemarkupianguage（XML）providesweiisupportforposition，occurrencetimes，andsoon.semi-structureddata，andbecomesthestandardofdata2）Attributetabie，storesattributeinformationexchangeintheWeb.Seif-descriptionofsemi-suchasattributename，nameoftheeiementthatthestruc

7、tureddataprovidesfiexibiiity，butitaisotakesupattributebeiongsto，attributetype，defauitattributeaiargeguantityofstoragespaceandprocessingtime.vaiue，occurrenceoftheattribute.Meanwhiie，weareshortofefficientandsuitabie3）Attributevaiuetabie，storesenumeratedvai-managementmechanismsan

8、dgueryfunctionsforuesofenumeratedtypeattribute.semi-structure