Overview
Databasemanagementsystemisalarge-scalesoftwarethatmanipulatesandmanagesdatabases.Itisusedtoestablish,useandmaintaindatabases,referredtoasDBMS.Itconductsunifiedmanagementandcontrolofthedatabasetoensurethesecurityandintegrityofthedatabase.
Databasemanagementsystemisadataoperationsoftwarethatcanprovidedataentry,modification,andquery.Ithasdatadefinition,dataoperation,datastorageandmanagement,datamaintenance,communicationandotherfunctions,andcanallowmultipleuserstouse.Inaddition,thedevelopmentofdatabasemanagementsystemsiscloselyrelatedtothedevelopmentofcomputertechnology.Andinrecentyears,computernetworkshavegraduallybecomeanimportantpartofpeople'slives.Forthisreason,ifyouwanttofurtherimprovethecomputerdatabasemanagementsystem,techniciansshouldcontinuetoinnovateandreformcomputertechnology,andcontinuetobroadentheapplicationrangeofcomputerdatabasemanagementsystems,soastotrulypromotetheinnovationofcomputerdatabasemanagementsystemtechnology.
Mainfunctions
1.Datadefinition:DBMSprovidesdatadefinitionlanguageDDL(DataDefinitionLanguage)foruserstodefinethethree-levelschemastructure,two-levelimageandintegrityconstraintsofthedatabaseAndconfidentialityrestrictions.DDLismainlyusedtoestablishandmodifythedatabasestructureofthedatabase.ThelibrarystructuredescribedbyDDLonlygivestheframeworkofthedatabase,andtheframeworkinformationofthedatabaseisstoredintheDataDictionary.
2.Datamanipulation:DBMSprovidesdatamanipulationlanguageDML(DataManipulationLanguage)foruserstoimplementoperationssuchasadding,deleting,updating,andqueryingdata.
3.Databaseoperationmanagement:TheoperationmanagementfunctionofthedatabaseistheoperationcontrolandmanagementfunctionoftheDBMS,includingconcurrencycontrolinamulti-userenvironment,securitycheckandaccessrestrictioncontrol,integritycheckandTheorganizationandmanagementofexecutionandrunninglogs,transactionmanagementandautomaticrecovery,thatis,toensuretheatomicityoftransactions.Thesefunctionsensurethenormaloperationofthedatabasesystem.
4.Dataorganization,storageandmanagement:DBMSshouldorganize,storeandmanageallkindsofdata,includingdatadictionary,userdata,accesspath,etc.ItisnecessarytodeterminethefilestructureandaccessHowtoorganizethesedataatthestoragelevelandhowtorealizetheconnectionbetweenthedata.Thebasicgoalofdataorganizationandstorageistoimprovetheutilizationofstoragespace,andtoselectappropriateaccessmethodstoimproveaccessefficiency.
5.Databaseprotection:Thedatainthedatabaseisastrategicresourceoftheinformationsociety,sotheprotectionofdataisveryimportant.TheprotectionofthedatabasebytheDBMSisrealizedthroughfouraspects:databaserecovery,databaseconcurrencycontrol,databaseintegritycontrol,anddatabasesecuritycontrol.OtherprotectionfunctionsoftheDBMSincludethemanagementofsystembuffersandsomeadaptiveadjustmentmechanismsfordatastorage.
6.Databasemaintenance:Thispartincludesfunctionssuchasdataloading,conversion,dumping,reassemblyandreconstructionofthedatabase,andperformancemonitoringofthedatabase.Thesefunctionsarecompletedbyeachapplicationprogram.
7.Communication:DBMShasrelatedinterfacesforonlineprocessingwiththeoperatingsystem,time-sharingsystemandremoteoperationinput,andisresponsibleforprocessingdatatransmission.Forthedatabasesystemunderthenetworkenvironment,itshouldalsoincludethecommunicationfunctionbetweentheDBMSandothersoftwaresystemsinthenetworkandtheinteroperabilityfunctionbetweenthedatabases.
Composition
Thedatabasemanagementsystemmainlyincludes:datadefinitionlanguageandrelatedproceduresfortranslation.Withthehelpofthispart,databaseuserscanmaketheirownchoicesandcanalsoThetranslationisthusformedintoaninternalform;theprogramfordataoperationcontrol,becauseoftheworkofthisprogram,theresourcesinthedatabasecanbefullymanaged,andakindofcontrolaboutthedatacanbeachieved;theutilityprogramofthedatabasecanmakeThedatabaseisestablishedonarelativelycompletebasis,andthedatabaseismaintainedunderarelativelycompletedatabasesystem.
Accordingtofunctions,thedatabasemanagementsystemcanberoughlydividedinto6parts:
(1)Modetranslation:Providedatadefinitionlanguage(ddl).Thedatabaseschemawritteninitistranslatedintointernalrepresentation.Thelogicalstructure,integrityconstraintsandphysicalstoragestructureofthedatabasearestoredintheinternaldatadictionary.Variousdataoperationsofthedatabase(suchassearching,modifying,insertinganddeleting,etc.)andthemaintenanceandmanagementofthedatabasearebasedonthedatabasemodel.
(2)Compilationofapplicationprograms:compileapplicationprogramsthatcontainstatementstoaccessthedatabaseintotargetprogramsthatcanberununderthesupportofdbms.
(3)Interactivequery:Provideaneasy-to-useinteractivequerylanguage,suchasSQL.DBMSisresponsibleforexecutingquerycommandsanddisplayingqueryresultsonthescreen.
(4)Dataorganizationandaccess:Providethephysicalorganizationandaccessmethodofdataonperipheralstoragedevices.
(5)Transactionoperationmanagement:Providetransactionoperationmanagementandoperationlog,transactionoperationsecuritymonitoringanddataintegritycheck,transactionconcurrencycontrolandsystemrecoveryfunctions.
(6)Databasemaintenance:Providesoftwaresupportfordatabaseadministrators,includingmaintenancetoolssuchasdatasecuritycontrol,integrityassurance,databasebackup,databasereorganization,andperformancemonitoring.
Workingmode
TheworkingmodeoftheDBMSisasfollows:
(1)Acceptapplicationdatarequestsandprocessingrequests;
(2)Converttheuser’sdatarequest(high-levelinstruction)intocomplexmachinecode(low-levelinstruction);
(3)Realizetheoperationofthedatabase;
(4)FromtherightAcceptqueryresultsduringdatabaseoperations;
(5)Processthequeryresults(formatconversion);
(6)Returntheprocessingresultstotheuser.
DBMSisalwaysbasedonacertaindatamodel,soDBMScanberegardedasaspecificimplementationofacertaindatamodelonacomputersystem.Accordingtodifferentdatamodels,DBMScanbedividedintohierarchical,mesh,relational,object-oriented,etc.
Indifferentcomputersystems,duetothelackofuniformstandards,evenDBMSswiththesamedatamodelareoftendifferentintermsofuserinterfaceandsystemfunctions.
Whenauseroperatesadatabase,theDBMStakestheoperationfromtheapplicationprogramtotheexternallevel,theconceptuallevel,andthentotheinternallevel,andthenmanipulatesthedatainthememorythroughtheoperatingsystem(OS).Atthesametime,theDBMSisTheapplicationprogramopensaDBsystembufferinthememoryfordatatransmissionandformatconversion.Thethree-levelstructuredefinitionisstoredinthedatadictionary.
Technicalfeatures
(1)Acomplexdatamodelisusedtorepresentthedatastructure,withlowdataredundancy,easyexpansion,anddatasharing.
(2)Ithashighdataandprogramindependence,andtheindependenceofthedatabaseisphysicalIndependenceandlogicalindependence.
(3)Thedatabasesystemprovidesuserswithaconvenientuserinterface.
(4)Thedatabasesystemprovidesfouraspectsofdatacontrolfunctions,respectivelyItisconcurrencycontrol,recovery,integrity,andsecurity.Thedatausedbyeachapplicationinthedatabaseisuniformlyspecifiedbythedatabasesystem,organizedandestablishedaccordingtoacertaindatamodel,andmanagedandcontrolledbythesystem.
(5)Increasetheflexibilityofthesystem.
Application
1.Improvethesecurityofthedataencryptionsystem
ThecomputerdatabasemanagementsystemitselfcanencryptData,andcombiningitwithapuredataencryptionsystemcanimprovethesecurityofdata.However,itshouldbenotedthattheexistenceofanyinformationmanagementsystemisforpeople.Forthisreason,datainformationisprocessedinthisenvironmentTransmissionandmaintenancerequiretechnicalpersonneltofurtheroptimizethedataencryptionsystemtomeetpeople’sneeds.
2.Improvetheefficiencyofinformationstorage
ThebiggestadvantageofacomputerdatabasemanagementsystemliesintheabilitytoperformdataLong-termstorageandmanagementofinformation.Thisfeatureiswidelyusedinmanyfields.However,itshouldbenotedthattechnicalpersonnelshouldcarefullyidentifytheuser’sidentitywhenenhancingtheinformationstorageratetopreventtheintrusionofillegalusers.Reducemaliciousaccess,hackerattacksandotherissues,andtrulyensurethesecurityofdataandinformation.
3.Improvedatabackupandrecovery
Intheprocessofcomputernetworkapplications,informationloss,Systemcrashesandotherphenomenahavecauseddatainformationtobedamagedandcannotbeusednormally.Thecomputerdatabasemanagementsystemismainlyacollectionofdatastorage.Inthisstorageprocess,themanagementsystemwillstoredatainacertainmodeandestablishamorecomplexDatastructurerelationship.Thiscanrealizetheseparateprocessingofdata,aswellasthecombineduseandprocessingofdata,soastoachieveefficientdatarecovery.
4.Enhancedmultimediamanagement
Applicationofcomputerdatabasemanagementsystemcanimprovethemanagementlevelofmultimedia.Technicianscanusecomputerdatabasemanagementsystemtoreducethecomplexityofmultimediamanagement,reduceworkload,andimprovemultimediamanagementefficiency.
ExcellentClick
(1)Controldataredundancy.Databasemanagementshouldeliminateredundancyasmuchaspossible,butnotcompletely,buttocontroltheinherentredundancyofalargenumberofdatabases.Forexample,inordertoexpresstherelationshipbetweendata,therepetitionofdataitemsisgenerallynecessary,andsometimessomedataitemsarerepeatedinordertoimproveperformance.
(2)Ensuredataconsistency.Byeliminatingorcontrollingredundancy,theriskofinconsistencycanbereduced.Ifthedataitemisstoredinthedatabaseonlyonce,anyupdatetothevalueonlyneedstobedoneonce,andthenewvalueisimmediatelyobtainedbyallusers.Ifthedataitemisstoredmorethanonce,andthesystemisawareofthis,thesystemwillbeabletoensurethatallcopiesoftheitemareconsistent.Unfortunately,manyDBMSscannotautomaticallyensurethistypeofconsistency.
(3)Improvedatasharing.Thedatabaseshouldbesharedbyauthorizedusers.TheintroductionofDBMSmakesiteasierformoreuserstosharemoredata.Newapplicationscanrelyondatathatalreadyexistsinthedatabase,andonlyadddatathatisnotstoredwithoutredefiningalldatarequirements.
Examplesofdatabasemanagementsoftware
ThemostpopulardatabasemanagementsystemproductsonthemarketaremainlyproductsfromcompaniessuchasOracle,IBM,Microsoft,andSybaseandMysql.
OracleDatabase
Oracledatabaseisconsideredtobethemostsuccessfulrelationaldatabasemanagementsystemintheindustry.Oracle'sdatabaseproductsareconsideredtobenobleproductswithstableoperation,completefunctionsandsuperiorperformance.Forenterpriseswithlargeamountsofdata,busytransactionprocessing,andhighsecurityrequirements.Oracleisundoubtedlytheidealchoice.WiththepopularityofInternet,OraclehascloselyintegrateditsproductswithnetworkcomputingattherighttimetobecomealeaderintheInternetapplicationfieldofdatabasevendors.
OracledatabasecanrunonUnix,Windowsandothermainstreamoperatingsystemplatforms,fullysupportallindustrialstandards,andobtainthehighestlevelofISOstandardsecuritycertification.Oracleadoptsacompletelyopenstrategy,whichallowscustomerstochoosethemostsuitablesolution,whileprovidingfullsupporttodevelopers.
DB2
DB2isaproductofIBM.ItisamultimediaandWebrelationaldatabasemanagementsystem.Itsfunctionsaresufficienttomeettheneedsoflargeandmedium-sizedcompaniesandcanbeflexiblyservedinChinaSmalle-commercesolutions.TheIMS(InformationManagementSystem)introducedbyIBMin1968isatypicalrepresentativeofhierarchicaldatabasesystemsandthefirstlarge-scalecommercialdatabasemanagementsystem.In1970,IBMresearchersputforwardtherelationalmodelofthedatabasesystemforthefirsttime,pioneeringthestudyofdatabaserelationalmethodsandrelationaldatatheory,layingthefoundationfordatabasetechnology.100%oftheFortune100companiesand80010oftheFortune500companiesuseIBM'sDB2databaseproducts.AnotherveryimportantadvantageofDB2liesintherichnessofmatureapplicationsbasedonDB2.In2001,IBMmergedwithInformix,awell-knowndatabasecompanyrankedfourthintheworld,andincorporateditsadvancedfeaturesintoDB2,whichfurtherimprovedtheperformanceandfunctionsoftheDB2system.
Sybaseseries
SybasewasestablishedinNovember1984.Productresearchanddevelopmentincludeenterprise-leveldatabases,datareplicationanddataaccess.Themainproductsare:Sybase'sflagshipdatabaseproductAdaptiveServerEnterprise,AdaptiveServerRepli-cation,AdaptiveServerConnectandheterogeneousdatabaseinterconnectionoptions.SybaseASEisitsmaindatabaseproduct,whichcanrunonUnixandWindowsplatforms.SybaseWarehouseStudioprovidesspecializedanalysissolutionsincustomeranalysis,marketsegmentationandfinancialplanning.ThecoreproductofWarehouseStudioisAdaptiveServerIQ,anditspatenteddatastoragetechnologydesignedfromthebottomcanquicklyquerylargeamountsofdata.ThereisacompletesetoftoolsaroundAdaptiveServerIQ,includingthedesignofdatawarehousesordatamarts,theintegrationandtransformationofvariousdatasources,thevisualanalysisofinformation,andthemanagementofkeycustomerdata(metadata).