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Multimedia database



Functionallevel

(1)Physicallayer:Itisthephysicalstoragedescriptionofthemultimediadatabase,thatis,theformdescribeshowthemultimediadataisstoredonthephysicalstoragedeviceofthecomputer.Formultimediadatabases,theactualdataisallowedtobescatteredindifferentdatabases.Forexample,inthemanagementofmultimediapersonnelfiles,aperson'svoiceandphotosmaybestoredinasounddatabaseandimagedatabase,andhisotherpersonnelrecordsmaybestoredinarelationaldatabase.

(2)Conceptlayer:Itrepresentstheabstractstructureoftherealworld,andisthedescriptionoftherealworldthings.Multimediaapplicationdeveloperscanuniformlymanagevariousmultimediadatastoredinthemultimediadatabasethroughthedatabaselanguageprovidedbythislayer.

Theconceptuallayerconsistsofasetofconceptualobjects.Theobjectsinvolvedintheconceptualobjectmaycomefromseveraldatabases.Forexample,peoplearedescribedbypersonnelrecords,photos,etc.,whichmaycomefromgeneralrelationaldatabasesandimagedatabases,respectively.Attheconceptuallevel,theschemamustbedefinedinaccordancewiththeconceptualschemaofseveraldatabases.

(3)Presentationlayer:Itcanbedividedintoviewlayeranduserlayer.Theuserlayeristheexternalmanifestationofthemultimediadatabase,thatis,thetables,graphics,pictures,andplayedsoundsthattheusercansee.Theuserlayercanbedescribedbyaspecialmultimedialayoutspecificationlanguage,andprovideuserswithaninterface.Theperformancemodeofmultimediadatamanagementsystemisanissuethatneedsattentionintheresearchofmultimediadatabasesystem.Sincetherepresentationofvariousunformatteddataisdifferent,andthereisacertaincorrelationbetweenthem,thepresentationlayerinthemultimediadatabasesystemiscomparedwiththetraditionaldata

Architecture

(1)Federalstructure

Themanagementofmultimediadataiscarriedoutseparately,andthedesignofeachmediadatabasedoesnothavetoconsidermatchingandcoordinationwithothermedia.

(2)Centralizedandunifiedstructure‘

Thereisonlyasinglemultimediadatabaseandasinglemultimediadatabasemanagementsystem.Variousmediaaremodeleduniformly,themanagementandmanipulationofvariousmediaarecentralizedinadatabasemanagementsystem,andtheneedsofvarioususersareunifiedintoamultimediauserinterface,andtheresultsofmultimediaqueryandretrievalcanbeuniformlyexpressed.

(3)Client/servicestructure

Varioussinglemediadataarestillrelativelyindependent.Thesystemusesaservertoimplementthemanagementsystemandmanipulationofeachmedia.Thisarchitectureisalsoeasytoextendtoworkinanetworkenvironment.

ResearchApproaches

Therearemanyresearchapproachesformultimediadatabases,andthefollowingfivemethodsarecommonlyused.

(1)Improvetheobject-orienteddatabasetomakeitsuitableformultimediadataprocessingsoastobegraduallyacceptedbyusers.

(2)EstablishmultimediaMISandGISintheexistingrelationaldatabase.

(3)Simpleexpansionoftherelationaldatabase,sothatithasthesimplestmultimediafunctions,suchasOracle,Sybase,etc.,haveexpandedthelongfieldtype,upto2GBofspace,storingvariousmultimediadata.However,thisexpansiononlystoresmultimediadataintheformofcharacters,anddoesnotsolvetheproblemofretrievalandprocessingofmultimediainformation.

(4)Thetheoryandtechnologyofrelationaldatabaseandthetheoryandtechnologyofobject-orienteddatabasearecombined.Ontheonehand,itcanberealizedquicklyandeconomicallybyusingthematuretechnologyofrelationaldatabase;ontheotherhand,object-orientedPartofthedatabasetechnologyisextendedtotherelationaldatabase,sothatithassomebasicfunctionsoftheobject-orienteddatabase.

(5)Introducehypermediamechanism.

Features

Multimediadataissignificantlydifferentfromtraditionaldatabasedata.Multimediadatabaseshavethefollowingcharacteristics.

①Theamountofdataishugeandthedifferenceintheamountofmediaisveryobvious,whichmakestheorganizationmethodandstoragemethodofthedatainthelibrarycomplicated.

②Thevarietyofmediamakesdataprocessingverycomplicated.Fourtypesofmultimediadatawereintroducedintheprevioussection,butinactualimplementation,theyoftenevolveintodozensofmediaformatsbasedonsystemdefinitionsandstandardconversions.

③Multimediahasnotonlychangedtheinterfaceofthedatabase,makingitsound,picture,andtextual,butalsochangedtheformofdatabasemanipulation,themostimportantofwhichisthequerymechanismandquerymethod.Thecomplex,scattered,sequentialnatureofthemediaanditsvisualcharacteristicsmakethequerynolongerjustquerybycharacters,andtheresultofthequeryisnotonlyatable,butasetof"representations"ofmultimedia.Themultimediainterfacewillputforwardmorecomplexandfriendlydesignrequirementsforthequery.

Function

(1)Themultimediadatabasesystemmustbeabletoexpressandprocessvariousmediadata.

(2)Themultimediadatabasesystemmustbeabletoreflectandmanagethecharacteristicsofvariousmediadata,orthetimeandspacerelationshipbetweenvariousmediadata.

(3)Thequeryofmultimediadatashouldbebasedoncontent,butthecontentshouldbedescribedinadvance.

(4)Themultimediadatabasesystemshouldbeopen,provideapplicationprograminterfacesandprovideinterfacesindependentofperipheralsandformats.

(5)Thedataoperationfunctionofthemultimediadatabasesystemshouldnotonlyprovidequeryandsearchfunctionsforunformatteddata,butalsoprovidedifferentoperationmethodsfordifferentmedia,suchaseditingandprocessingofgraphicsandimages.Editingofsounddata,etc.

(6)Thenetworkfunctionofthemultimediadatabasesystem.Sincemultimediaapplicationsaregenerallynetwork-centric,problemssuchasthedefinition,storage,andoperationofdatainmultimediadatabasesdistributedonthenetworkshouldberesolved,andtheconsistencyandsecurityofthedatashouldbemanaged.

(7Themultimediadatabaseshouldprovidetheabilitytodealwithlong-termaffairsandversioncontrol.

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