翻译以学号-姓名.原文和在同一文件中前

用提供自定义的应用视图，这可以去除程序和数据结构的干扰；此外，该模型能够维持数据的完整性和一致性。根据这一HDIM模型，一种名叫UDMP的基于模式的系统被设计并实现。实验结果表明，本文模型和相应的系统在表现物联性方绪。“自顶向下”的垂直过程，因为一次查询操作不会影响到其他数据模式的存在。这种据的完整性和一致性的同时不破坏全局范围内数据资源的自治性。与数据查询相比,那“黑盒”的实现机制不能使一个外部应用接触到系统的结构和行为状态，因此不能异数成的本点式实异据成（G()和全局本地视图模式(G)V将标式定为数据模之的视；V将数据源模式定义为在目标模式之上的视图；V了V和V同。V展技。典的V是TSIS。V具有较高的效率但可扩展性差，这不适合物联网的数据环境。V通过重写技术获取数据。典型的V项目是信息集成。V能松应底的态。，在V中将全局数据查询转换为局部数据查询的过程比V更加复杂，这将导致效率的降低。V着眼将前两方的共特。式匹与生是式的个键点。模式匹配就是在某种特定的规则下寻找数据元间不同的方式。有研究[8]提出一利用器习找全视与数源之关的方。种法基全的则 [9]提出了一种基于数值的方法以生成相应的。这种方法利用数据元素与模式的语义约束之间的关系建立。本第2对M第3部分设计与数据集成模本文提出了一种基于模式的异构数据集成模型HDIM。首先，HDIM为全部底 的视图，以便 其次，HDIM在视图之上提供了一个合适的应用视图，这样所有应用都能根据各自定义1：键。键是构成数据表的基本元素，它与实体数据源中的关键词建立了直接关系。键可以表示成一个四元组：Ukey=(Ukname,Utname,{KMap},{Fk})。Ukname表示键的名称，Utname是键所属的数据表的名称，{KMap}表示从键到数据源键集合的路径。tname,kname)；Ukname是键的名称，UVname是视图名称，tname是表到的原始表名，kname是键到的原始键名。一个键通过KMap与原始定义3：完整性关系。完整性关系定义为一个三元组：Fk={parentUkey,dependentUkeyF}；ParentUkey表示双亲键dependentUkey表示子键；这两者都可表示为二元组：parentUkeydependentUkeyUKRefUtname,Ukname)Ukname表示统一键名,Utname是键所属的数据表的名称。F是一个约束。当双亲键的值键值发生变化，HDIM都会在全局范围内检查键的完整性关系。只有完整性关系得到满定义4：数据表。数据表是整个系统中逻辑上的、虚拟的表。它将所的变化。数据表定义如下：Utable=(Utname,{Ukey}).{Utable});；UVname是视图的名称；Addr包含了获取原始数据源信息的，Addr以对原始数据源的寻址与连接为目标。Utable代表数据表。数据表中的辑数据模型，它有如下的形式：DataObjDOnameItems})；DOname表示数据对象名7：数据对象属性。数据对象属性是构成应用视图的基本元素，可表示为一个三元组：Item=(Itemname,DOname,{IMap})。Itemname是属性名称，DOname是数据键的路径。一个对象属性在对象中有唯一的名称，它能到多种数据源，不过相同的数据源路径只有一个。定义8：对象属性的路径。IMap可表示为一个四元组：IMap=(Itemname,DOname,Utname,Ukname)；Iternname是属性名称。DOname是对象名称，Utname是属性到的数据表的名称，Ukname属性到的数据键的名称。通过IMap，建立一个对象属性到一个或几个键的关系。UVs)；DOs是应用数据集合的应用数据视图，UVs是应用数据集合的视图数据表和键确定了全局中分布式异构数据源的表示。Ukey定义了数据的完整性与一致性关系。应用程序提交数据对象DataObj作为数据请求。通过IMap和KMap，HDIM能够实现任务的，分解和解决。Ukey建立了完整性约束关通过视图的方式，HDIM提高了数据集成的灵活性和可扩展性。HDIM在中，存在三种视图:应用视图,视图和原始数据视图；同样在其中存在两种关系:IMap,KMap。IMap将应用视图中的数据对象到视图中的统一键上。通过异构数据录入的视图，的数据定义了一种的表达式,KMap将视图中的键到原始数据源中的键。的表格和的键为异构数据源和分布式数据源建立一个全局的表达式。视图隐藏了异构数据源之间的制的数据服务。在过程中，DOname和项目指定应用程序数据对象及其属性名称，Utname和Ukname指定的密钥属于的键名和的表格，Addr实现在的视图中的数据源位置，TNAMEKNAME代表分别对应的原始数据源中键，即键到的键。图1展示了一个数据对象与原始数据源中的表之间的2.1HDIMForwardFullLink:item×GV→KeyForwardUpperLink:item×GV→Ukeyletutname=Getutname(Obj,item,Imap)letukname=Obj×item×Imap→utnameGetukname=Getukname：Obj×item×Imap→uknameGetutname=Imap(Objname,itemname)GetUkey:utname×ukname×GV GetUkey(utn,ukn,GV)=letUks= letresults=findUKey(ukn,Uks)infindUKey:ukname×Ukey* →UkeyfindUKey(ukn,Uk(Ukn,Utn,km*,fk*))=MatchName(ukn,Ukn)→Uk,nullfindUKey(ukn,Uk:Uks)=findUKey(ukn,Uk):findUKey(ukn,Uks)=letr=findUkey(ukn,Uk)in;r=null→findUkey(ukn,Uks)MatchName:string×string→MatchName(s1,s2)s1=s2→ForwardLowerlink:Ukey×UV→lettname=Gettname(Utname,Ukname,Kmap)letkname=Gettname：Utname×Ukname×Kmap→tnameGetkname=Kmap-1(Utname,Ukname)Getkname：Utname×Ukname×Kmap→knameGettname=GetKey:tname×kname×UV GetKey(tn,kn,UV)=letks= letresults=findKey(kn,ks)inresultfindKey:kname× →findKey(kn,K(Kn,Tn))=MatchName(kn,Kn)→letr=findKey(kn,K)in;r=null→findKey(kn,10：任务。一个任务由一个四元组组成：GTaskop,AObj,W),op代表数据操作类型，并且它的可能取值可以是："SELECT"(数据提取)，"DELETE"(数据删除),"INSERT"(数据),"UPDATE"(数据更新)；A是数据属性的集合，由对象属性定义组成：A={attribute};attribute=(item,value)，itemvalue是数据值，当op是UPDATE或INSERT时,value值是对象属性到的数据记录值，当op是SELECTDELETEvalue值为空；ObjObj={objname}；W(item,Obj,f,comp)，item表示对象属性名称，Obj表示数据对象名称，f表示约束值，comp表示约束关系。GTask转化成UTask或Task。选择对象属性的过程可以作如下形式化描述：GetItemFromTask：GTask×GV →{Item}letresult=FindItem(itemname,items,GV)inresultGetItemFromTask：GTask×GV→{Item}letresult=FindItem(itemname,items,GV)inresultFindItem:Itemname*×item*×GV →{item}GetItem(Itemname,items,GV)FindVkeys(Itemnames,items,GV)过程如图2所示：2.2ImplTask：GTaskdataresultletutsks=IMapTasks(GT)in;letrtsks=RelateTask(utsks)in;letsubresults=ImplsubTask(tsks:rtsks)in;collectData(subresults);IMapTasks：GTaskUTask*IMapTasks(GT)=letuv=FilterSource1(GT)inletresult=CreateUTasks(GT,uv))in;FilterSource1:GTaskUVname*CreateUTasks：GTask×UVname* KMapTasks：UTaskKMapTasks(UT)=letuv=FilterSource2(UT)in;letresult=CreateUTasks(UT,uv))in;FilterSource2:UTaskkname*CreateTasks：UTask×kname* RelateTasks：UTaskTask*ImplsubTask:Task*dataset*ImplsubTask(tsk)=letSql=createSQLFromTask(tsk)in;letcon=createSQLConnection(tsk)in;letd=execuSQL(con,Sql)in;letsubresult=d(con,tinfo,d)每一个键都到物理数据源中的一个物理键。在这个虚拟数据库中的表之间和键之间都存在约束关系，这些约束关系在视图中定义了一系列完整性约束。当一个物理数据中的键发生变化，其他全局范围内的，与之存在完整性或一致性关系的键的F}；ParentUkey代表双亲键，dependentUkey代表子键；这两者都可表示为一个三元组：parentUkey=dependentUkey=UKRef=(Utname,Ukname)。Ukname代表键名称，Utname是键所属的数据表的名称；F是一个约束。的约束关系Fk是边。图3是关系图的一个样例：2.3A在图中，点A,B,......代表键，边F1,F2,代表键之间的关系定义。在间的约束关系。关系树定义如下：RTreeUK{node})；UK是根节点，UKUtname,Ukname),，{node}是节点集合.。在Rtree中，一个节点对应一个键，边对应完整FknodeUKFk,{node})，{node是子节点的CheckPKs：Ukey*×GV×RTree→BooleanCheckPKs(Uk,GV,GTCheckPK(UkGV,GT)CheckPKs(Vks,GV,GT)CheckPK：Ukey×GV×RTree→BooleanCreatePTree:Ukey×GV→RTreeCreatePTree(Uk,GV)ukn’(Ukn,Utn,-,-)=Ukletnodes=CreateNodes(GetPFk(Uk,GV))in;RTree((ukn,utn),nodes);CreatePNodes：Ukey×Fk* node*CreatePNodes(Uk,fk)=CreatePNode(Uk,fk)CreatePNodes(Uk,fks)CreatePNode：Ukey×Fk×GVnode fk,GV)=letukref(utn,ukn)=GetPairKey(Uk,fk)in; in;letpnodes=CreatePNodes(uk,GetPFk(uk,GV))in;letresult=n(ukref,fk,pnodes)原型系UDMP的设计与实这一部分设计并实现了一种三视图的双UDMP（数据管理平台。它UMDP为系统中的异构数据对象创建了一个的全局逻辑视图。通过这个的全局了定制的应用视图，这样每个应用都能根据自己的需要具体地定制数据对象来进行CRUD（创建，恢复，更新，删除）操作。平台架构如图5所示：UDP由四个主要部分组成：管理，执行引擎，应用程序接口和数据库接口理括三数视：数库视图图应用图据SQLUDMP在一定实验与分4.1中间节点数据库服务1.Suse器Enterprise2.forSuse 这一章在本章中，比较UDMP和hibernate数据平台[10]的性能，hibernate是一个使用O/R和命令的持久性管理的主流数据中间件。并发线程对这些记录做，查询，修改和删除操作。所用数据库为Oracle数据库。表 实验结120,0001k

同时100个并 数据持续300分

100条记

UDMPhibernate64.1理等其他方面压力时，UDMP的效率比hibernate略低，但它仍然处在标准的范围内。本章选择国家前兆平台的应用场景作为测试场景来进行实验并评价UDMP的实际表现。试验结果表明，UDMP可以实现的数据和数据管理，并具有比Hibernate更好的表现。结需要地组织和管理。关于数据集成的先前研究中关注数据的查询和建模，但关于环境中的异构数据约束关系的研究是不充分的。为了解决这些问题，本文提出了关于异构的作整合HIMHIM模型构建出应用视图——视图——数据源视图的层次结构，其中，在应用视图中生成的相应数据对象为应用程序提供定制的数据服务；全局标准逻辑视图在视图中建立；通过以上三级对数据进行加工。此外，在视图中还在数据项之中建立了约束检验模型，从而构建整个数的数据协作。在那之后，本文设计与实现了基于HDIM模型的原型系统UDP，同时考虑到了数据和业务在域的实际要求特点。为实现透明地数源，UP置的正的据式数标UDP也实现了应用程序和数据结构的分离，并对象化了上层应用以提高执行效率；UP为视图提供了配置功能UDMP参考文LiyanLiu,HuaLi.MetadataModelinGridDatabaseanditsApplication.The9thInternationalConferenceoncomputerSupportedCooperativeWorkinDesign,pp.362-366.UK,(2005)GuoHao-Ming,MaShi-Long.Functionaldemand-drivenresourceaggregationmethodandimplementation.JournalofBeihangUniversity,2008,34(5),pp.260-262Yong-Qiang,MaShi-Long,JinWen.Methodfordataintegrationmechanismformaintainingdataintegrity.JournalofBeihangUniversity,2008,34(9),pp.1045-1048GuoHao-Ming,HaoGuo-Shun.HeterogeneousdataintegrationandcoordinationinNGG.JournalofBeihangUniversity,2008,34(2),pp.180-182WangGui-Lin,LiYu-Shun,etc.AserviceGridDynamicInformationAggregationModelandItsApplication.JournalofComputers2005,28(4),pp.541-548Ki-WonYeom,Ji-HyungPark.AnEvolutionaryApproachforDynamicReconfigurationinHeterogeneousDatabaseSchemas.IEEECongressonEvolutionaryComputationSheraton,Vancouver,Canada,2006.pp.162-166TienN.Nguyen.Object—OrientedSoftwareConfigurationManagement.ICSM’06.22ndIEEEInternationalConferenceonSoftwareMaintenance,2006,pp.35l354．M.Lenzerini.DataIntegration:ATheoertiealPesrpective[A],ProceedingsoftheACMSIGMOD-SIGACT-SIGARTsymposiumonPrinciplesofdatabasesystemsACMNewYork,NY,USA,2002,pp.233-HuChun-Ming,HuaiJin-Peng,WoTian-Yu,LeiLei..AnendtoendSupportServiceGridArchitecture.JournalofSoftware,2006,17(5),pp.1448-1458GavinKing,ChristianBaue.HibernateinAction[M]．ManningPublicationsAHeterogeneousDataIntegrationLiuHai1,1,LiuYunzhen1,WuQunhui1,Ma1Departmentofcomputerscienceandtechnology,Beihanguniversity,37xueyuan100083Beijing,.WiththerapiddevelopmentoftheInternetofThings(IOT),thedatamanagement,datamininganddataysisinIOTsystemsrequireimprovingtheusabilityofthemulti-sourced,distributed,autonomousandheterogeneousdatafromthesubsystems,makingtheaggregation,integrationandcollaborationofthedataafocusinresearch.AccordingtothecharacteristicsofbasicIOTdataenvironment,aHDIMisproposedbasedonthecomparisonandysisofthecurrentexistingdataintegrationapproaches.Thismodelcannotonlymaskthedataheterogeneityindistributions,butalsoprovidethecustomizedapplicationviewfortheupperapplications,whichcandecoupletheprogramsanddatastructures;additionally,themodelcanmaintaintheintegrityandconsistencyofthedata.BasedonthisHDIMmodel,apattern-map-basedsystemwiththenameofUDMPisdesignedandimplemented.TheexperimentsshowthattheproposedmodelandthecorrespondingsystemcanaddressthefeaturesoftheIOTwithrelativegoodperformance.Keywords:InternetOfThings;dataintegration;viewmapWiththerapiddevelopmentoftheInternetofThings(IOT),andthegrowingdemandsofdatamanagement,datamining,dataysisintheapplicationlayerofIOT,thebusinessdatainbothintra-industryandinter-industryneedtobeintegrated.Theintegrationofdatabasesinthevariousdistributedandheterogeneoussubsystemshas eahotresearchtopic.AsthetechnicalbasisofdataintegrationinIOT,Datamiddlewareisthekeytechniquetotheintegrationandmanagementofthedistributedandheterogeneousdata.Therefore,thestudyondatamiddlewarehasimportantsignificancefordataintegration.Forthecurrentpracticalapplications,alongwiththecontinuoussystemintegration,linkageandcollaborationbetweensubsystems,therearealargenumberofdifferenttypesofapplicationunitsintheapplicationlayer.Meanwhile,thestorageformatsanddataspecificationsarediverseinthedatalayer,whichconstituteanumberofheterogeneousdatasources.Theseheterogeneousdatasourcesmakethedatamanipulationanddataexchangemoredifficult.Thecurrentresearchworkstaketheimplementationof"Query"asthemainpurposeofdataintegration.Dataqueryisa"top-bottom"verticalprocess,becauseonequeryoperationdoesnotaffecttheexistenceofdatainanotherschema.Thisformofmodelconstructionandorganizationtakethedataasisolatedobjectsduringdatamanipulationandcannotestablishmutualrelationsbetweenthesedatainthepatterns.However,inthesystemsofIOT,thebasicdatasupportingenvironmentcallsforthemaintenanceoftheglobaldataintegrityandconsistency.Thisrequiresthedataintegrationplatformnotonlytoachievetheunifiedqueryofheterogeneousdata,butalsotomaintaintheintegrityandconsistencyoftheheterogeneousdatawithoutviolatingtheautonomyofthedataresourcesintheglobalscope.Comparedwithdataqueries,operationswhichmodifythedatawouldcausemorecomplexchecksfordataintegrityandthecorrespondingmodificationsfordataconsistency.Inthisprocess,itisrequirednotonlytorewriteand posethedataoperationtaskstofinishthecurrenttask,butalsotoestablishcorrespondingoperationaltasksinordertomaintainglobalintegrityandconsistency.Taketheseismicindustryasanexample,thedistributeddatasourcesinvariousregionsnationwideconstitutethebasicdatasupportingenvironmentforthesystem.Theorganizationandmanagementofthesedatasourcesmaybedifferent.ly,datamodelsneedstobeconstructedsoastobemappedintoeverydatasourcebasedonthebusinessneeds.Theintegrityandconsistencyconstraintsinthedatamodelshouldbeestablishedsoastochecktheglobaldataintegritytogetherwiththetriggermechanismofeachdatasource,therebyintegratingtheentiredatasourcestoensuringtheintegrity,consistencyandvalidityofdatainthebasicdatasupportingenvironment.Secondly,moreandmoreapplicationsforIOTsystemsarewrittenintheobject-way.Theseapplicationscannotseamlesslyworktogethertherationaldatabasesbecauseofthedifferencesintheirmodels,To ethisimpedancemismatchbetweentheobjectmodelandtherelationalmodel,anobject/relationalmapisessentialforthesystem.Thirdly,thedatasourcehaspoorscalability,whenanewdatasourceisadded,itisdifficulttofacilitatetheintegrationofthenewdataortodynamicallyadjusttothechangesofthedatasources.Thetraditionalmiddlewaremainlyadaptsthe"blackbox"mechanism.The"blackbox"implementationmechanismcannotmakeanexternalapplicationtoaccessthesystem'sinternalstructureandstatebehavior,andthuscannotbedynamicallyadjustedaccordingtotherelevantchangesoftheapplicationlayerorthedatasourcelayer.Thislimitsthesystem’sscalabilityanptabilitytothedynamicenvironment.Thepatternisthebasicstartingpointinheterogeneousdataintegrationapproach.Patternmapisthecoretechnologytoachieveintegrationofheterogeneousdatasources[1-7].Accordingtothedifferentmapstyles,thereareGlobal-As-Viewmode(GAV),Local-As-Viewmode(LAV)andGlobal-Local-As-Viewmode(GLAV).GAVdefinesthemodeasaviewabovethedatasourcemode;LAVdefinesthedatasourcemodeasaviewabovemode;GLAVcombinesthecharacteristicsofbothGAVandLAV.GAVinquiresdatathroughunfoldingtechnology.OneofthetypicalGAVprojectsisTSIMMIS.GAVperformshighefficiencybutpoorscalability,whichisunsuitableforIOTdataenvironment.LAVqueriesdatabytherewritingtechnology.ThetypicalLAVprojectistheInformationManifold.LAVcaneasilyadapttothedynamicchangesoftheunderlyingdata.However,theprocessoftransformingglobaldataqueryintoalocaldataqueryinLAVismuorecomplexthaninGAV,whichresultsinlowerefficiency.GLAVfocusesonthecharacteristicsofthosetwoformermethods[7].Thepatternmatchingandmapgenerationaretwokeypointsofpatternmap.Patternmatchingislookingfordifferentmodesofmapbetweendataelementsfollowingparticularrules.Study[8]proposesamethodusingmachinelearningtofindtherelationshipbetweentheglobalviewandthedatasources.Thismethodisbasedonaglobalschemarulesdirectoryautomaticallyfindsbetweenthesourceschemamapbetweenelements;Thismethodautomaticallyfindsrelationshipthebetweentheglobalviewandthedatasourceelementsbasedonarulesdirectory;Study[9]proposesavalue-basedmethodforgeneratingthecorrespondingmap.ThemethodestablishesmapbyutilizingtherelationshipbetweentheelementsandsemanticconstraintsofTherestpartofthepaperisconstructedasfollows:Section2givesadetailedinstructionofHDIM.Section3providesdetaileddesignandimplementationoforiginaldatamiddlewaresystemUDMP.Section4conductsexperimentsandevaluationofUDMP.AndSection5concludesthepaper.DataIntegrationModelDefinitionofThispaperpresentsaHeterogeneousDataIntegrationModel(HDIM)basedonpatternmap.,HDIMcreatesagloballyunifiedviewforallunderlyingdatasourcessoastoshieldtheheterogeneousdatasourcesanddatastructuresthroughmap.Second,HDIMprovidesaappropriateapplicationviewabovetheunifiedviewsothatallapplicationscanbecustomizedaccordingtotheirneeds.Definition1.Unifiedkey.AunifiedkeyisthebasicelementtoconstituteaUnifieddatatable,itestablishesadirectmaprelationshipwithKeysintheentitydatasource.Unifiedkeyconsistsoffour-tupleform:Ukey=(Ukname,Utname,{KMap},{Fk});Uknamerepresentsforunifiedkeyname,Utnameisthenameofunifieddatatablewhichunifiedkeybelongsto,{KMap}isthemappathfromunifiedkeytoasetofkeyindatasources;Definition2.Mappathsoftheunifiedkey.KMapconsistsoffour-tuple:KMap=(Ukname,UVname,tname,kname);Uknameisthenameoftheunifiedkey,UVnameisUnifiedviewname,tnameistheoriginaltablenamewhichunifiedtableismapto,knameistheoriginalkeynamewhichtheunifiedkeyismapto.AunifiedkeyestablishesmaprelationshiptotheoriginalkeybyDefinition3.Integrityrelationship.Integrityrelationshipisdefinedbytripleform:Fk{parentUkey,dependentUkey,F};ParentUkeyrepresentsforparentkey,dependentUkeyrepresentsforthesub-key;bothofthemaremadeoftupleform:parentUkey=dependentUkey=UKRef=(Utname,Ukname).Uknamerepresentsforunifiedkeyname,Utnameisthenameofunifieddatatablewhichtheunifiedkeybelongsto;Fisaconstrainedlabel.Whenaparentkeygeneratesvaluechanges,itwillaffectthevalueofsub-key.Thereareasetofintegrityrelationshipsineachunifiedkey.Foreachchangeofthekeyvalue,HDIMcheckstheintegrityrelationshipofthekeyinaglobalscope.Dhangescannotbecarriedoutunlesstheintegrityrelationsissatisfied.Definition4.TheUnifiedtable.Unifiedtableisthegloballyunifiedlogicalandvirtualtableinthesystem.Itdefinesalltheunderlyingdatasourcedatainstandardssothatthesystemcanadapttothechangesofdatabaseproductorthedatabasestructure.Theunifiedtableisdefinedasfollows:Utable=(Utname,{Ukey}).Definition5.TheUnifieddataview.TheUnifieddataviewconsistsoftripleform:UnifiedView=(UVname,Addr,{Utable});UVnameisthenameofunifiedview;Addrcontainstheaccessinformationtotheoriginaldatasource,Addraimsataddressingandconnectiontotheoriginaldatasource.Utablestandsfortheunifieddatatable.Aunifiedkeyintheunifiedtablemaymaptodifferentoriginalkeyintheunderlyingdatasource.Definition6.TheApplicationview.TheApplicationviewconsistsofapplicationdataobject.Dataobjectisthespecificlogicaldatamodeloftheapplicationitself,whichhasthefollowingform:DataObj=(DOname{Items});DOnamerepresentsdataobjectname,{Items}standsforacollectionofattributesofthedataobject.Definition7.Attributesofdataobject.Dataobjectattributesarethebasicelementsthatconstitutetheapplicationview,theyeachconsistsofatripleform:Item=(Itemname,DOname,{IMap});Itemnameistheattributename,DOnameisdataobjectname,{IMap}pathsetsfortheobjectattributemap;{IMap}isthemappathfromobjectattributetoasetofunifiedkeyinunifiedview.Oneobjectattributehasauniquenameintheobject,itcanmaptomultipledatasources,however,thesamedatasourcepathhasonlyoneDefinition8.Mappathsofobjectattribute.IMapconsistsoffour-tuple:IMap=(Itemname,DOname,Utname,Ukname);Iternnameistheattributename,DOnameisobjectname,Utnameistheunifiedtablenamewhichattributesmapto,Uknameistheunifiedkeynamewhichattributesmapto.OneobjectattributeunifiedkeyestablishesthemaprelationshiptooneorseveralunifiedkeybyIMap.Definition9.Dataresourceintegrationmodel.Thedataresourceintegrationmodelconsistsofatupleform:GV=(DOs,UVs);DOsistheapplicationdataviewfortheapplicationdataset,UVsistheunifiedviewofapplicationdataset.Unifiedtableandunifiedkeyestablishagloballyunifiedexpressionforheterogeneousanddistributeddatasources.Ukeydefinesintegrityandconsistencyrelationshipofdata.ApplicationssubmitteddataobjectsDataObjfordataaccessrequest.HDIMrealizesthetask positionandresolutionaccordingtoIMapandKMap.Ukeyestablishestheintegrityconstraintrelationshipinordertomaintaintheglobalintegrityofthedataincaseofdatachanges.Uviewmasksthedifferencesbetweenheterogeneousdatasources.HDIMimprovestheflexibilityandscalabilityofdataintegrationinaviewmapway.HDIMInHDIM,therearethreeviews:theapplicationview,theunifiedviewandtheoriginaldataview;italsohastwomaps:IMap,KMap.IMapmapsdataobjectsinapplicationviewtotheunifiedkeyintheunifiedview.Theuniformaccesstodatathroughaunifiedviewofheterogeneousdataentrydefinesaunifiedexpression,KMapmapsunifiedkeyintheunifiedviewtothekeyintheoriginaldatasource.Theunifiedtableandunifiedkeyestablishagloballyaunifiedexpressionforheterogeneousanddistributeddatasources.TheunifiedviewmasksthedifferencesbetweenheterogeneousdatasourcesandimprovesflexibilityandscalabilityofHDIM.Theapplicationsviewcanprovidecustomizeddataaccessserviceforspecificapplications.Duringthemapprocess,DOnameandItemspecifyapplicationdataobjectsandtheirattributesname,UtnameandUknamespecifyunifiedkeynameandunifiedtablewhichtheunifiedkeybelongsto,Addrrealizesthedatasourcelocationintheunifiedview,tnameandknamerepresentthecorrespondingkeyintheoriginaldatasourcerespectively,whichtheunifiedkeyismapto.Fig.1showsamapbetweenadataobjectandatableintheoriginaldatasource.Fig.1.MapofMapprocessfromdataobjecttooriginalkeycanbeformalizedasfollows:ForwardFullLink:item×GV→KeyForwardUpperLink:item×GV→letutname=Getutname(Obj,item,Imap)letukname=Obj×item×Imap→utnameGetukname=Getukname：Obj×item×Imap→uknameGetutname=Imap(Objname,itemname)GetUkey:utname×ukname×GV →UkeyGetUkey(utn,ukn,GV)=letUks= letresults=findUKey(ukn,Uks)inresultfindUKey:ukname×Ukey* →UkeyfindUKey(ukn,Uk(Ukn,Utn,km*,fk*))=MatchName(ukn,Ukn)→Uk,nullfindUKey(ukn,Uk:Uks)=findUKey(ukn,Uk):findUKey(ukn,Uks)=letr=findUkey(ukn,Uk)in;r=null→findUkey(ukn,Uks)MatchName:string×string→BooleanMatchName(s1,s2)=s1=s2→ForwardLowerlink:Ukey×UV→lettname=Gettname(Utname,Ukname,Kmap)letkname=Gettname：Utname×Ukname×Kmap→tnameGetkname=Kmap-1(Utname,Ukname)Getkname：Utname×Ukname×Kmap→knameGettname=Kmap-1(Utname,Ukname)GetKey:tname×kname×UV GetKey(tn,kn,UV)=letks= letresults=findKey(kn,ks)inresultfindKey:kname×Key* →KeyfindKey(kn,K(Kn,Tn))=MatchName(kn,Kn)→Key,nullfindKey(kn,K:Ks)=findKey(kn,K):findKey(kn,Ks)=letr=findKey(kn,K)in;r=null→findKey(kn,Ks)DataManipulationTasksofAdatamanipulationtasktakestheapplicationdataobje anentity,throughmap,tododataextractionormodificationoperationinoneormorecorrespondingoriginaldataDefinition10.Task.Ataskisconstitutedbyafour-tuple:GTask=(op,A,Obj,W),opstandsforthedataoperationtype,anditspossiblevaluecanbe:"SELECT"(dataextraction),"DELETE"(datadeletion),"INSERT"(adddata),"UPDATE"(dataupdate);Aisthecollectionofdataattributewhichisconstitutedbyobjectattributedefinition:A={attribute};attribute=(item,value),itemistheobjectattributename,valueisthedatavalue,whenopisUPDATEorINSERT,valueisdatarecordvalueswhichtheobjectattributeismapto,whenopisaSELECTorDELETE,valueisnull;Oisacollectionofdataobjects,Obj={objname};Wisasetofconstraintswhichconsistsoffour-tupleform:(item,Obj,f,comp),itemfortheobjectattributenames,Objforthedataobjectname,fistheconstraintvalue,compistheconstraintrelationship.Inthetaskexecutionprocess,lyselectallobjectspropertiesinthetask,andthentransformtheGTaskintoUTaskorTaskbymaptheseproperties.Theselectionofobjectpropertiescanbeformalizedasfollows:GetItemFromTask：GTask× →letresult=FindItem(itemname,items,GV)inresultGetItemFromTask：GTask×GV→{Item}letresult=FindItem(itemname,items,GV)inresultFindItem:Itemname*×item*×GV →{item}GetItem(Itemname,items,GV)FindVkeys(Itemnames,items,GV)HDIMconstructsthedatamodelandsubmitsthedataaccessrequestbasedonapplicationrequirements.Whenthetaskengineacceptsthisrequest,it posesforeachdatasourcetoperformasub-taskinaccordancewiththemapofthedataobject.Thesesub-tasksexecuteinthedistributedoriginaldatasource.Finalresultsofthesub-taskarecollectedandreturntotheapplication.DataaccessprocessisshowninFig.2:Fig.2.GTaskexecutionTaskexecutionprocesscanbeformalizedasfollows:ImplTask：GTaskdataresultletutsks=IMapTasks(GT)in;letrtsks=RelateTask(utsks)in;letsubresults=ImplsubTask(tsks:rtsks)in;collectData(subresults);IMapTasks：GTaskUTask*IMapTasks(GT)=letuv=FilterSource1(GT)inletresult=CreateUTasks(GT,uv))in;FilterSource1:GTaskUVname*CreateUTasks：GTask×UVname* KMapTasks：UTaskTask*KMapTasks(UT)=letuv=FilterSource2(UT)in;letresult=CreateUTasks(UT,uv))in;FilterSource2:UTaskkname*CreateTasks：UTask×kname* RelateTasks：UTaskTask*ImplsubTask:Task*dataset*ImplsubTask(tsk)=letSql=createSQLFromTask(tsk)in;letcon=createSQLConnection(tsk)in;letd=execuSQL(con,Sql)in;letsubresult=d(con,tinfo,d)Theentiredataenvironmentcanbeconsideredasavirtualdatabasethatconsistsofalargenumberofheterogeneousdatasources.Eachkeyofthisvirtualdatabaseismappedtoarealphysicalkeyinphysicaldatasources.Constraintrelationshipexistsbetweentablesandkeysinthisvirtualdatabase,whichformsaintegrityconstraintsintheUnifiedView.Whenaunifiedkeyinthephysicaldatagenerateschanges,thevalueofotherunifiedkeywillbeinfluenced,whichhastheintegrityorconsistencyrelationshipswithitin aglobalscope.Integrityrelationshipisdefinedbytripleform:Fk={parentUkey,dependentUkey,ParentUkeyrepresentsforparentkey,dependentUkeyrepresentsforthesub-key;bothofthemmadebytupleform:parentUkey=dependentUkey=UKRef=(Utname,Ukname).Uknamerepresentsforunifiedkeyname,Utnameisthenameofunifieddatatablewhichtheunifiedkeybelongsto;Fisaconstrainedlabel.IntheUnifiedViewallintegrityconstraintrelationsconstituteadiagram,wheretheunifiedkeysarethevertexandtheconstraintrelationshipFkbetweenunifiedkeysaretheedges.Fig.3isanexampleoftherelationshipdiagram:Fig.3.ConstraintrelationtreeofnodeInthefigure,PointA,B,......standforunifiedkey,whileEdgeF1, standforrelationshipdefinitionbetweenunifiedkeys.Inthedefinitionofintegrityconstraintrelationship,ifaunifiedkeyisasub-key,theintegrityrelationshipofthisunifiedkeyisconsideredasaninverserelationship,thentherelationshipoftheedgescorrespondingtothe keyiscalledbackwardedge.Onthecontrary,ifaunifiedkeyisaparent-key,theintegrityrelationshipofthisunifiedkeyisthenconsideredasanforwardrelationship,therelationshipoftheedgescorrespondingtotheunifiedkeyiscalledforwardedge.Duringtheexecutionofthetask,HDIMneedstotheselectthecorrespondingconstraintrelationshipsaccordingtooperatetypetocompletedataintegritychecks.Accordingtotheoperatetype,dataintegritycheckcanleadtothefollowingdifferentSelectoperation:sincetherearenodhanges,sodonotmakeanyintegritychecksintheglobalscope.Deleteoperation,Needstodoforwardintegritychecksinglobalscopeontheunifiedkeywhichisabouttochange.Insertoperation,Needstodobackwardintegritychecksinglobalscopeontheunifiedkeywhichisaboutt