Заден план
Sincethelate1960s,computersusedformanagementhavebecomelargerandlargerandmorewidelyused.Theamountofdatahasincreasedsharply.Atthesametime,multipleapplications,Therequirementsforsharingdatacollectionswithmultiplelanguagescoveringeachotherarebecomingstronger;computerhardwarehaslarge-capacitydisks,thepriceofhardwarehasfallen,andthepriceofsoftwarehasrisen,andthecostofcompilingandmaintainingsystemsoftwareandapplicationprogramshasrelativelyincreased;Intermsofprocessingmethods,onlinereal-timeprocessingrequiresmore,andtheconceptofdistributedprocessinghasbeenformed.Inthiscontext,theuseoffilesystemsasameansofdatamanagementcannolongermeettheneedsofapplications,soinordertosolvetheneedsofmultipleusersandmultipleapplicationstosharedata,databasemanagementtechnologycameintobeing.
Съдържание
1. Създаване на базата данни
Theestablishmentofthedatabaseincludestwoparts,theestablishmentofthedatamodelandthedataloading.
2. Корекция на база данни
Afterthedatabaseisestablishedandrunforaperiodoftime,someunsuitablesituationswilloftenoccur.Atthistime,itneedstobeadjusted.ThedatabaseadjustmentisgenerallydonebytheDBA.
3. Реорганизация на базата данни
Afteracertainperiodoftimehaspassed,theperformanceofthedatabasewillgraduallydecline.Thereasonforthedeclineismainlyduetocontinuousmodification,deletionandinsertion.Forthesereasons,itisnecessarytorearrangethedatabaseandre-adjustthestoragespace.Thiskindofworkiscalleddatabasereorganization.Atpresent,RDBMSgenerallyprovidecertainmeanstorealizethedatareorganizationfunction.
4.DatabaseSecurityControlandIntegrityControl
Databaseisanimportantresourceofanorganization,anditssecurityisextremelyimportant.ThedatabaseadministratorDBAshouldtakemeasurestoensurethatthedataisprotectedfromillegalmisappropriationanddestroy.Inaddition,inordertoensurethecorrectnessofthedata,sothatthedataenteredinthedatabasecanbekeptcorrect,itisnecessarytohavetheintegritycontrolofthedatabase.
5.Възстановяване на грешка в базата данни
Oncethedatainthedatabaseisdamaged,itneedstoberestoredintime.RDBMSgenerallyprovidethisfunction,andtheDBAisresponsibleforperformingthefailurerecoveryfunction.
6. Мониторинг на база данни
DBAneedstoobservethedynamicchangesofthedatabaseatanytime,and:takemeasuresatanytimewhenerrors,failuresorinadaptabilityoccur;atthesametime,theyalsoneedtomonitortheperformancechangesofthedatabase.Makeadjustmentstothedatabasefromtimetotime.
Предимства
1.Интегриране на данни
Aunifieddatastructuremethodisadoptedinthedatabasesystemtomakethedatastructured;theglobaldatastructureissharedbymultipleapplications,andeachprogramcallsthedataofthelocalstructure.Formdataintegrationwithlocalstructuralpatterns.
2.Високо споделяне на данни, ниско резервиране
Thedatabasesystemviewsanddescribesdatafromanoverallperspective.Thedatafacestheentiresystemandnolongerfacesacertainapplication.Therefore,thedatacanbesharedbymultipleusersandmultipleapplications.shared.Thecombinationofdatabasetechnologyandnetworktechnologyexpandstheapplication.Thedegreeofdatasharinggreatlyreducesdataredundancy,savesstoragespace,andcanavoidincompatibilityandinconsistencybetweendata.
3.Highdataindependence
Dataindependencemeansthattheuser’sapplicationandthedatainthedatabaseareindependentofeachother,thatis,whenthephysicalstructureandlogicalstructureofthedataWhenthereisachange,itdoesnotaffecttheuseofdatabytheapplication.
4.Datamanagementandcontrolcapabilities
Thedatabasesystemmanagesandcontrolsthedatauniformly,ensuringthesecurityandintegrityofthedata.Thedatabasesystemcheckstheidentityofaccessingusersandthelegitimacyoftheiroperations;automaticallycheckstheconsistencyandcompatibilityofthedatatoensurethatthedatameetstheintegrityconstraints;usesconcurrentcontrolmethodstoeffectivelycontrolmulti-userprogramsandoperateonthedataatthesametimetoensuresharingAndconcurrentoperation;therecoveryfunctionguaranteesthatwhenthedatabaseisdamaged,itcanautomaticallyrecovertothecorrectstate.