Fundamentals of Database Systems KFUPM.ppt

,chapter29emergingdatabasetechnologiesandapplications,copyright2004pearsoneducation,inc.,chapter29-3,chapteroutline,1mobiledatabases1.1mobilecomputingarchitecture1.2characteristicsofmobileenvironments1.3datamanagementissues1.4application:intermittentlysynchronizeddatabases2multimediadatabases2.1thenatureofmultimediadataandapplications2.2datamanagementissues2.3openresearchproblems2.4multimediadatabaseapplications,chapter29-4,chapteroutline(contd.),3geographicinformationsystems3.1gisapplications3.2datamanagementrequirementsofgis3.3specificgisdataoperations3.4anexampleofgissoftware:arc-info3.5problemsandfutureissuesingis,chapter29-5,chapteroutline(contd.),4genomedatamanagement4.1biologicalsciencesandgenetics4.2characteristicsofbiologicaldata4.3thehumangenomeprojectandexistingbiologicaldatabases,chapter29-6,emergingdatabasetechnologiesandapplications,emergingdatabasetechnologiesthemajorapplicationdomains,chapter29-7,1mobiledatabases,recentadvancesinportableandwirelesstechnologyledtomobilecomputing,anewdimensionindatacommunicationandprocessing.portablecomputingdevicescoupledwithwirelesscommunicationsallowclientstoaccessdatafromvirtuallyanywhereandatanytime.,chapter29-8,1mobiledatabases(2),thereareanumberofhardwareandsoftwareproblemsthatmustberesolvedbeforethecapabilitiesofmobilecomputingcanbefullyutilized.someofthesoftwareproblemswhichmayinvolvedatamanagement,transactionmanagement,anddatabaserecoveryhavetheiroriginsindistributeddatabasesystems.,chapter29-9,1mobiledatabases(3),inmobilecomputing,theproblemsaremoredifficult,mainly:thelimitedandintermittentconnectivityaffordedbywirelesscommunications.thelimitedlifeofthepowersupply(battery).thechangingtopologyofthenetwork.inaddition,mobilecomputingintroducesnewarchitecturalpossibilitiesandchallenges.,chapter29-10,1.1mobilecomputingarchitecture,thegeneralarchitectureofamobileplatformisillustratedinfig29.1.,chapter29-11,figure27.4ageneralarchitecture,chapter29-12,1.1mobilecomputingarchitecture(2),itisdistributedarchitecturewhereanumberofcomputers,generallyreferredtoasfixedhostsandbasestationsareinterconnectedthroughahigh-speedwirednetwork.fixedhostsaregeneralpurposecomputersconfiguredtomanagemobileunits.basestationsfunctionasgatewaystothefixednetworkforthemobileunits.,chapter29-13,1.1mobilecomputingarchitecture(3),wirelesscommunicationsthewirelessmediumhavebandwidthsignificantlylowerthanthoseofawirednetwork.thecurrentgenerationofwirelesstechnologyhasdataratesrangefromthetenstohundredsofkilobitspersecond(2gcellulartelephony)totensofmegabitspersecond(wirelessethernet,popularlyknownaswifi).modern(wired)ethernet,bycomparison,providesdataratesontheorderofhundredsofmegabitspersecond.,chapter29-14,1.1mobilecomputingarchitecture(4),wirelesscommunicationstheothercharacteristicsdistinguishwirelessconnectivityoptions:interference,localityofaccess,range,supportforpacketswitching,seamlessroamingthroughoutageographicalregion.,chapter29-15,1.1mobilecomputingarchitecture(5),wirelesscommunicationssomewirelessnetworks,suchaswifiandbluetooth,useunlicensedareasofthefrequencyspectrum,whichmaycauseinterferencewithotherappliances,suchascordlesstelephones.modernwirelessnetworkscantransferdatainunitscalledpackets,thatareusedinwirednetworksinordertoconservebandwidth.,chapter29-16,1.1mobilecomputingarchitecture(6),client/networkrelationshipsmobileunitscanmovefreelyinageographicmobilitydomain,anareathatiscircumscribedbywirelessnetworkcoverage.tomanageentiremobilitydomainisdividedintooneormoresmallerdomains,calledcells,eachofwhichissupportedbyatleastonebasestation.mobileunitsbeunrestrictedthroughoutthecellsofdomain,whilemaintaininginformationaccesscontiguity.,chapter29-17,1.1mobilecomputingarchitecture(7),client/networkrelationshipsthecommunicationarchitecturedescribedearlierisdesignedtogivethemobileunittheimpressionthatitisattachedtoafixednetwork,emulatingatraditionalclient-serverarchitecture.wirelesscommunications,however,makeotherarchitecturespossible.onealternativeisamobilead-hocnetwork(manet),illustratedin29.2.,chapter29-18,1.1mobilecomputingarchitecture(8),chapter29-19,1.1mobilecomputingarchitecture(9),client/networkrelationshipsinamanet,co-locatedmobileunitsdonotneedtocommunicateviaafixednetwork,butinstead,formtheirownusingcost-effectivetechnologiessuchasbluetooth.inamanet,mobileunitsareresponsibleforroutingtheirowndata,effectivelyactingasbasestationsaswellasclients.moreover,theymustberobustenoughtohandlechangesinthenetworktopology,suchasthearrivalordepartureofothermobileunits.,chapter29-20,1.1mobilecomputingarchitecture(10),client/networkrelationshipsmanetapplicationscanbeconsideredaspeer-to-peer,meaningthatamobileunitissimultaneouslyaclientandaserver.transactionprocessinganddataconsistencycontrolbecomemoredifficultsincethereisnocentralcontrolinthisarchitecture.resourcediscoveryanddataroutingbymobileunitsmakecomputinginamanetevenmorecomplicated.samplemanetapplicationsaremulti-usergames,sharedwhiteboard,distributedcalendars,andbattleinformationsharing.,chapter29-21,1.2characteristicsofmobileenvironments,thecharacteristicsofmobilecomputinginclude:communicationlatency.intermittentconnectivity.limitedbatterylife.changingclientlocation.,chapter29-22,1.2characteristicsofmobileenvironments(2),theservermaynotbeabletoreachaclient.aclientmaybeunreachablebecauseitisdozinginanenergy-conservingstateinwhichmanysubsystemsareshutdownorbecauseitisoutofrangeofabasestation.ineithercase,neitherclientnorservercanreachtheother,andmodificationsmustbemadetothearchitectureinordertocompensateforthiscase.proxiesforunreachablecomponentsareaddedtothearchitecture.foraclient(andsymmetricallyforaserver),theproxycancacheupdatesintendedfortheserver.,chapter29-23,1.2characteristicsofmobileenvironments(3),mobilecomputingposeschallengesforserversaswellasclients.thelatencyinvolvedinwirelesscommunicationmakesscalabilityaproblem.becauselatencyduetowirelesscommunicationsincreasesthetimetoserviceeachclientrequest,theservercanhandlefewerclients.onewayserversrelievethisproblemisbybroadcastingdatawheneverpossible.aservercansimplybroadcastdataperiodically.broadcastalsoreducestheloadontheserver,asclientsdonothavetomaintainactiveconnectionstoit.,chapter29-24,1.2characteristicsofmobileenvironments(4),clientmobilityalsoposesmanydatamanagementchallenges.serversmustkeeptrackofclientlocationsinordertoefficientlyroutemessagestothem.clientdatashouldbestoredinthenetworklocationthatminimizesthetrafficnecessarytoaccessit.theactofmovingbetweencellsmustbetransparenttotheclient.theservermustbeabletogracefullydiverttheshipmentofdatafromonebasetoanother,withouttheclientnoticing.clientmobilityalsoallowsnewapplicationsthatarelocation-based.,chapter29-25,1.3datamanagementissues,fromadatamanagementstandpoint,mobilecomputingmaybeconsideredavariationofdistributedcomputing.mobiledatabasescanbedistributedundertwopossiblescenarios:theentiredatabaseisdistributedmainlyamongthewiredcomponents,possiblywithfullorpartialreplication.abasestationorfixedhostmanagesitsowndatabasewithadbms-likefunctionality,withadditionalfunctionalityforlocatingmobileunitsandadditionalqueryandtransactionmanagementfeaturestomeettherequirementsofmobileenvironments.thedatabaseisdistributedamongwiredandwirelesscomponents.datamanagementresponsibilityissharedamongbasestationsorfixedhostsandmobileunits.,chapter29-26,1.3datamanagementissues(2),datamanagementissuesasitisappliedtomobiledatabases:datadistributionandreplicationtransactionsmodelsqueryprocessingrecoveryandfaulttolerancemobiledatabasedesignlocation-basedservicedivisionoflaborsecurity,chapter29-27,1.4application:intermittentlysynchronizeddatabases,wheneverclientsconnectthroughaprocessknowninindustryassynchronizationofaclientwithaservertheyreceiveabatchofupdatestobeinstalledontheirlocaldatabase.theprimarycharacteristicofthisscenarioisthattheclientsaremostlydisconnected;theserverisnotnecessarilyablereachthem.thisenvironmenthasproblemssimilartothoseindistributedandclient-serverdatabases,andsomefrommobiledatabases.thisenvironmentisreferredtoasintermittentlysynchronizeddatabaseenvironment(isdbe).,chapter29-28,1.4application:intermittentlysynchronizeddatabases(2),thecharacteristicsofintermittentlysynchronizeddatabases(isdbs)makethemdistinctfromthemobiledatabasesare:aclientconnectstotheserverwhenitwantstoexchangeupdates.thecommunicationcanbeunicastone-on-onecommunicationbetweentheserverandtheclientormulticastonesenderorservermayperiodicallycommunicatetoasetofreceiversorupdateagroupofclients.aservercannotconnecttoaclientatwill.,chapter29-29,1.4application:intermittentlysynchronizeddatabases(3),issuesofwirelessversuswiredclientconnectionsandpowerconservationaregenerallyimmaterial.aclientisfreetomanageitsowndataandtransactionswhileitisdisconnected.itcanalsoperformitsownrecoverytosomeextent.aclienthasmultiplewaysconnectingtoaserverand,incaseofmanyservers,maychooseaparticularservertoconnecttobasedonproximity,communicationnodesavailable,resourcesavailable,etc.,chapter29-30,2multimediadatabases,intheyearsaheadmultimediainformationsystemsareexpectedtodominateourdailylives.ourhouseswillbewiredforbandwidthtohandleinteractivemultimediaapplications.ourhigh-definitiontv/computerworkstationswillhaveaccesstoalargenumberofdatabases,includingdigitallibraries,imageandvideodatabasesthatwilldistributevastamountsofmultisourcemultimediacontent.,chapter29-31,2.1multimediadatabases,dbmsshavebeenconstantlyaddingtothetypesofdatatheysupport.todaythefollowingtypesofmultimediadataareavailableincurrentsystems.text:maybeformattedorunformatted.foreaseofparsingstructureddocuments,standardslikesgmlandvariationssuchashtmlarebeingused.graphics:examplesincludedrawingsandillustrationsthatareencodedusingsomedescriptivestandards(e.g.cgm,pict,postscript).,chapter29-32,2.1multimediadatabases(2),images:includesdrawings,photographs,andsoforth,encodedinstandardformatssuchasbitmap,jpeg,andmpeg.compressionisbuiltintojpegandmpeg.theseimagesarenotsubdividedintocomponents.hencequeryingthembycontent(e.g.,findallimagescontainingcircles)isnontrivial.animations:temporalsequencesofimageorgraphicdata.,chapter29-33,2.1multimediadatabases(3),video:asetoftemporallysequencedphotographicdataforpresentationatspecifiedratesforexample,30framespersecond.structuredaudio:asequenceofaudiocomponentscomprisingnote,tone,duration,andsoforth.audio:sampledatageneratedfromauralrecordingsinastringofbitsindigitizedform.analogrecordingsaretypicallyconvertedintodigitalformbeforestorage.,chapter29-34,2.1multimediadatabases(4),compositeormixedmultimediadata:acombinationofmultimediadatatypessuchasaudioandvideowhichmaybephysicallymixedtoyieldanewstorageformatorlogicallymixedwhileretainingoriginaltypesandformats.compositedataalsocontainsadditionalcontrolinformationdescribinghowtheinformationshouldberendered.,chapter29-35,2.1multimediadatabases(5),natureofmultimediaapplications:multimediadatamaybestored,delivered,andutilizedinmanydifferentways.applicationsmaybecategorizedbasedontheirdatamanagementcharacteristicsasfollows:repositoryapplications:alargeamountofmultimediadataaswellasmetadataisstoredforretrievalpurposes.examplesincluderepositoriesofsatelliteimages,engineeringdrawingsanddesigns,spacephotographs,andradiologyscannedpictures.,chapter29-36,2.1multimediadatabases(6),presentationapplications:alargeamountofapplicationsinvolvedeliveryofmultimediadatasubjecttotemporalconstraints;simplemultimediaviewingofvideodata,forexample,requiresasystemtosimulatevcr-likefunctionality.complexandinteractivemultimediapresentationsinvolveorchestrationdirectionstocontroltheretrievalorderofcomponentsinaseriesorinparallel.interactiveenvironmentsmustsupportcapabilitiessuchasreal-timeeditinganalysisorannotatingofvideoandaudiodata.,chapter29-37,2.1multimediadatabases(7),collaborativeworkusingmultimediainformation:thisisanewcategoryofapplicationsinwhichengineersmayexecuteacomplexdesigntaskbymergingdrawings,fittingsubjectstodesignconstraints,andgeneratingnewdocumentation,changenotifications,andsoforth.intelligenthealthcarenetworksaswellastelemedicinewillinvolvedoctorscollaboratingamongthemselves,analyzingmultimediapatientdataandinformationinrealtimeasitisgenerated.,chapter29-38,2.2datamanagementissues,multimediaapplicationsdealingwiththousandsofimages,documents,audioandvideosegments,andfreetextdatadependcriticallyonappropriatemodelingofthestructureandcontentofdataandthendesigningappropriatedatabaseschemasforstoringandretrievingmultimediainformation.multimediainformationsystemsareverycomplexandembracealargesetofissues:modelingcomplexobjects,chapter29-39,2.2datamanagementissues(2),designconceptual,logical,andphysicaldesignofmultimediahasnotbeenaddressedfully.storagemultimediadataonstandarddisklikedevicespresentsproblemsofrepresentation,compression,mappingtodevicehierarchies,archiving,andbufferingduringtheinput/outputoperation.queriesandretrieval“database”wayofretrievinginformationisbasedonquerylanguagesandinternalindexstructures.,chapter29-40,2.2datamanagementissues(3),performancemultimediaapplicationsinvolvingonlydocumentsandtext,performanceconstraintsaresubjectivelydeterminedbytheuser.applicationsinvolvingvideoplaybackoraudio-videosynchronization,physicallimitationsdominate.,chapter29-41,2.3multimediadatabaseapplications,large-scaleapplicationsofmultimediadatabasescanbeexpectedencompassesalargenumberofdisciplinesandenhanceexistingcapabilities.documentsandrecordsmanagementknowledgedisseminationeducationandtrainingmarketing,advertising,retailing,entertainment,andtravelreal-timecontrolandmonitoring,chapter29-42,3geographicinformationsystems,geographicinformationsystems(gis)areusedtocollect,model,andanalyzeinformationdescribingphysicalpropertiesofthegeographicalworld.thescopeofgisbroadlyencompassestwotypesofdata:spatialdata,originatingfrommaps,digitalimages,administrativeandpoliticalboundaries,roads,transportationnetworks,physicaldata,suchasrivers,soilcharacteristics,climaticregions,landelevations,and,chapter29-43,3geographicinformationsystems(2),nonspatialdata,suchassocio-economicdata(likecensuscounts),economicdata,andsalesormarketinginformation.gisisarapidlydevelopingdomainthatoffershighlyinnovativeapproachestomeetsomechallengingtechnicaldemands.,chapter29-44,3.1gisapplications,itispossibletodividegissintothreecategories:cartographicapplications,digitalterrainmodelingapplications,andgeographicobjectsapplications,chapter29-45,3.1gisapplications(2),chapter29-46,3.2datamanagementrequirementsofgis,thefunctionalrequirementsofthegisapplicationsabovetranslateintothefollowingdatabaserequirements.datamodelingandrepresentation,gisdatacanbebroadlyrepresentedintwoformats:vectordatarepresentsgeometricobjectssuchaspoints,lines,andpolygons.,chapter29-47,3.2datamanagementrequirementsofgis(2),rasterdataischaracterizedasanarrayofpoints,whereeachpointrepresentsthevalueofanattributeforareal-worldlocation.informally,rasterimagesaren-dimensionalarraywhereeachentryisaunitoftheimageandrepresentsanattribute.two-dimensionalunitsarecalledpixels,whilethree-dimensionalunitsarecalledvoxels.three-dimensionalelevationdataisstoredinaraster-baseddigitalelevationmodel(dem)format.,chapter29-48,3.2datamanagementrequirementsofgis(3),anotherrasterformatcalledtriangularirregularnetwork(tin)isatopologicalvector-basedapproachthatmodelssurfacesbyconnectingsamplepointsasvectoroftrianglesandhasapointdensitythatmayvarywiththeroughnessoftheterrain.rectangulargrids(orelevationmatrices)aretwo-dimensionalarraystructures.indigitalterrainmodeling(dtm),themodelalsomaybeusedbysubstitutingtheelevationwithsomeattributeofinterestsuchaspopulationdensityorairtemperature.gisdataoftenincludesatemporalstructureinadditiontoaspatialstructure.,chapter29-49,3.2datamanagementrequirementsofgis(4),dataanalysis,gisdataundergoesvarioustypesofanalysis.forexample,inapplicationssuchassoilerosionstudies,environmentalimpactstudies,orhydrologicalrunoffsimulations,dtmdatamayundergovarioustypesofgeomorphometricanalysismeasurementssuchasslopevalues,gradients(therateofchangeinaltitude),aspect(thecompassdirectionofthegradient),profileconvexity(therateofchangeofgradient),planconvexity(theconvexityofcontoursandotherparameters).,chapter29-50,3.2datamanagementrequirementsofgis(5),dataintegration,gissmustintegratebothvectorandrasterdatafromavarietyofsources.sometimesedgesandregionsareinferredfromarasterimagetoformavectormodel,orconversely,rasterimagessuchasaerialphotographsareusedtoupdatevectormodels.severalcoordinatesystemssuchasuniversaltransversemercator(utm),latitude/longitude,andlocalcadastralsystemsareusedtoidentifylocations.dataoriginatingfromdifferentcoordinatesystemsrequiresappropriatetransformations.,chapter29-51,3.2datamanagementrequirementsofgis(6),datacapture,thefirststepindevelopingaspatialdatabaseforcartographicmodelingistocapturethetwo-dimensionalorthree-dimensionalgeographicalinformationindigitalformaprocessthatissometimesimpededbysourcemapcharacteristicssuchasresolution,typeofprojection,mapscales,cartographiclicensing,diversityofmeasurementtechniques,andcoordinatesystemdifferences.spatialdatacanalsobecapturedfromremotesensorsinsatellitessuchaslandsat,nora,andadvancedveryhighresolutionradiometer(avhrr)aswellasspothrv(highresolutionvisiblerangeinstrument.,chapter29-52,3.3specificgisdataoperations,gisapplicationsareconductedthroughtheuseofspecialoperatorssuchasthefollowing:interpolationinterpretationproximityanalysisrasterimageprocessinganalysisofnetworks,chapter29-53,3.3specificgisdataoperations(2),thefunctionalityofagisdatabaseisalsosubjecttootherconsiderations:extensibilitydataqualitycontrolvisualizationsuchrequirementsclearlyillustratethatstandardrdbmssorodbmssdonotmeetthespecialneedsofgis.itisthereforenecessarytodesignsystemsthatsupportthevectorandrasterrepresentationsandthespatialfunctionalityaswellastherequireddbmsfeatures.,chapter29-54,4.1genomedatamanagement,biologicalsciencesandgenetics:thebiologicalsciencesencompassanenormousvarietyofinformation.environmentalsciencegivesusaviewofhowspeciesliveandinteractinaworldfilledwithnaturalphenomena.biologyandecologystudyparticularspecies.anatomyfocusesontheoverallstructureofanorganism,documentingt