Tietokannanhallinta

Tausta

Sincethelate1960s,computersusedformanagementhavebecomelargerandlargerandmorewidelyused.Theamountofdatahasincreasedsharply.Atthesametime,multipleapplications,Therequirementsforsharingdatacollectionswithmultiplelanguages​​coveringeachotherarebecomingstronger;computerhardwarehaslarge-capacitydisks,thepriceofhardwarehasfallen,andthepriceofsoftwarehasrisen,andthecostofcompilingandmaintainingsystemsoftwareandapplicationprogramshasrelativelyincreased;Intermsofprocessingmethods,onlinereal-timeprocessingrequiresmore,andtheconceptofdistributedprocessinghasbeenformed.Inthiscontext,theuseoffilesystemsasameansofdatamanagementcannolongermeettheneedsofapplications,soinordertosolvetheneedsofmultipleusersandmultipleapplicationstosharedata,databasemanagementtechnologycameintobeing.

Sisältö

1.Tietokannan perustaminen

Theestablishmentofthedatabaseincludestwoparts,theestablishmentofthedatamodelandthedataloading.

2. Tietokannan säätö

Afterthedatabaseisestablishedandrunforaperiodoftime,someunsuitablesituationswilloftenoccur.Atthistime,itneedstobeadjusted.ThedatabaseadjustmentisgenerallydonebytheDBA.

3.Tietokannan uudelleenjärjestely

Afteracertainperiodoftimehaspassed,theperformanceofthedatabasewillgraduallydecline.Thereasonforthedeclineismainlyduetocontinuousmodification,deletionandinsertion.Forthesereasons,itisnecessarytorearrangethedatabaseandre-adjustthestoragespace.Thiskindofworkiscalleddatabasereorganization.Atpresent,RDBMSgenerallyprovidecertainmeanstorealizethedatareorganizationfunction.

4.DatabaseSecurityControlIntegrityControl

Databaseisanimportantresourceofanorganization,anditssecurityisextremelyimportant.ThedatabaseadministratorDBAshouldtakemeasurestoensurethatthedataisprotectedfromillegalmisappropriationanddestroy.Inaddition,inordertoensurethecorrectnessofthedata,sothatthedataenteredinthedatabasecanbekeptcorrect,itisnecessarytohavetheintegritycontrolofthedatabase.

5. Tietokannan palautus epäonnistui

Oncethedatainthedatabaseisdamaged,itneedstoberestoredintime.RDBMSgenerallyprovidethisfunction,andtheDBAisresponsibleforperformingthefailurerecoveryfunction.

6. Tietokannan seuranta

DBAneedstoobservethedynamicchangesofthedatabaseatanytime,and:takemeasuresatanytimewhenerrors,failuresorinadaptabilityoccur;atthesametime,theyalsoneedtomonitortheperformancechangesofthedatabase.Makeadjustmentstothedatabasefromtimetotime.

Edut

1. Tietojen integrointi

Aunifieddatastructuremethodisadoptedinthedatabasesystemtomakethedatastructured;theglobaldatastructureissharedbymultipleapplications,andeachprogramcallsthedataofthelocalstructure.Formdataintegrationwithlocalstructuralpatterns.

2. Korkea datan jakaminen, alhainen redundanssi

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.