Egciniwe phezulu - ke ... amamodeli, izibonelo

Phezulu egciniwe - database esekelwe isakhiwo esihlahleni. Ngokusho isimiso ukuyakha Kuthi efana uhlelo ifayela sekhompyutha. Sisebenzisa le imodeli has yayo emihle nemibi, okuzoxoxwa ngayo kulesi sihloko, kanye izibonelo ezinemininingwane.

Amafomu Database

Njengoba aziwa, ukuhlukanisa izinhlobo ezine postoreniya semininingwane:

• Zingubudlelwane - semininingwane yethebula, lapho ulwazi uvezwa uhlobo imigqa-amakholomu. Ngokwalesi simiso, database kwakhiwa "Acces", isibonelo.
• Into ngamakhasimende - zisondelene kakhulu PLO (uhlelo lapho sisebenzela nge izinto), futhi lokhu kuzobazuzisa main, kodwa ngenxa ukusebenza yabo encane, aziyi kakhulu ngaphansana yokudlanga zingubudlelwane.
• Hybrid - DBMS lithwale ezimbili nje kwezinhlobo ngenhla.
• Phezulu - into ukunakwa kwalesi sihloko. Lokhu semininingwane libhekene isakhiwo isihlahla-like.

Isibonelo edume kunazo database phezulu iwumkhiqizo adalwe IBM ( "AyBiEm"), eyayinesihloko esithi Information Management System (elihunyushwa ngokuthi "Management Information System"), esifushanisiwe njengoba IMS. I inguqulo yokuqala ye-IMS wabuya esikhathini esidlule, ngekhulu leminyaka lamashumi amabili, ngonyaka ayisithupha nesishiyagalombili. Isetshenziselwa isitoreji idatha nokulawula kuze kube yilolu suku.

Izimiso imodeli phezulu

I phezulu imodeli idatha kusekelwe isimiso elandelayo:

• I-engeyokuqala isakhiwo yilowo nalowo muthi ibekwe endaweni ingxenye ezifanayo;
• A ingxenye iwumkhakha idatha eyabelwe ngegama ngalinye ensimini ayesemvunulisa kwelinye umugqa tuple;
• Enye ukuxhumana: eyodwa input bese amaningi okukhipha izingxenye inkambu input ngamunye;
• for element ngayinye kwesakhiwo kukhona esisodwa futhi esisodwa kuphela indawo sabaphathi kohlelo;
• isihlahla isakhiwo iqala element impande;
• engeyokuqala ngamunye kuphela inceku amadlozi, kodwa umthombo ngamunye kungenzeka inzalo amaningi.

Ukusebenzisa isakhiwo idatha phezulu

egciniwe phezulu - lokhu isitoreji esebenzayo kulabo izinhlelo, okuyinto ekuqaleni elinesimo isakhiwo esihlahleni. Kubo ukukhetha sekulingisa ezinjalo - kunengqondo.

Isibonelo semininingwane phezulu degrees ekuqaleni systematized - iyunithi ezempi, okuyinto ukuba amamaki ecacile eyaziwayo. Futhi, kungaba izindlela eziyinkimbinkimbi ehlanganisa zonke eminye lula phansi izinhlayiya isigaba sabaphathi. Ukuze sekulingisa izinhlelo ezifana niwalethe ifomu kubhekwe DB asikho isidingo ukubola. Noma kunjalo, lesi simo akuhlali.

Ngaphezu kwalokho, kukhona ukuthambekela nombuzo phansi ikhipha lula ukudlula phezulu efanayo.

imisebenzi Basic esizindeni sokwaziswa se-, eyakhelwe imodeli phezulu

Isakhiwo database phezulu ivumela yimpumelelo futhi cishe komzamo (kuye ngokuthi amakhono) ukumhlinza ezilandelayo (emelelwa eyisisekelo kunazo, uhlu Ungahlala enwetshiwe nezinye izithasiselo ezincane):

• ukucinga database yesici esithile;
• ukwedlulela database - kwesinye isihlahla siye kwesinye;
• inguqulelo - izinkuni legatsha ukuze legatsha;
• Ngakho, ukwedlulela amagatsha - isici by isici;
• Sebenza okuqoshiwe: ufaka entsha kanye / noma zamanje ukususwa, ukukopisha, ukuzisika, njll ...

Incazelo generalized isakhiwo

Igama elithi "umuthi" ukuchaza isakhiwo okukhulunywe ngazo kulesi sihloko isivele kude ngaphezu kwesikhathi esisodwa. Sekuyisikhathi ukukutshela ukuthi kwenzeka kanjani. Zonke ngoba database phezulu - kungcono database enjalo, esebenzisa uhlobo idatha "isihlahla." Ake sicabangele lokho elikumelelayo.

Lolu hlobo esiyinhlanganisela: ngayinye izakhi (nodes) uma sezingashumekeka elilandelayo ezimbalwa (elilodwa noma ngaphezulu). Konke kuqala nge impande isici esisodwa. Iphuzu eliyinhloko liwukuthi ngamunye izingcezu ezifana "isihlahla" kuyinto subtype, futhi, "umuthi." Abaningi, abaningi branched, futhi zonke izakhiwo kahle ngaphambilini.

Imihlobo esisekelo kungaba elula noma kwakwakhe, empeleni njalo ukurekhoda. Kodwa ngo ukuqopha elula kukhona omunye uhlobo idatha, futhi ekhuthaza - lonke iqoqo kubo.

imodeli phezulu kuyinto eyinqaba isimiso inzalo, lapho ingxenye ngayinye yangaphambilini ukhokho ukuhamba kwesikhathi. Ngaphezu kwalokho, ingane maqondana nohlobo umzali uhlobo inceku, kuyilapho omunye okulingana amanye amarekhodi bangamawele kubhekwe.

ukugcwalisa database

Idatha eziyinhloko phezulu semininingwane namanani (izinombolo noma izimpawu) elondolozwe ku amarekhodi. Dula database enjalo ngokuvamile kusukela phansi kuze futhi kusuka kwesokunxele kuya kwesokudla.

isithunzi

egciniwe phezulu - database esesikhundleni ifolda impande, kancane kancane ekhelini phansi. Njengoba sazi ukuthi isakhiwo esinjalo kufana kakhulu kusistimu yefayela, lezisekelo ezinjalo zisetshenziswa ngempumelelo ukwenza imisebenzi ehlukahlukene kudatha ikhompyutha. Isiphetho sendaba: ukwabiwa okunengqondo inkumbulo yayo, futhi ngesikhathi ukusebenza ehlonipheke kakhulu esichithwa umsebenzi.

Imodeli phezulu ilungele ukusetshenziswa Imininingwane yalo ehleliwe.

amaphutha

Nokho, izici ezifanayo okuxoxwe DBMSs ukuthi babe izinzuzo zabo eziyinhloko, futhi ukunquma ukushiyeka kwabo. Ngokwesibonelo, kushuba nobunzima abaxhumene okunengqondo - uchwepheshe abanolwazi kuyoba kanzima nge isizinda ezazingaziwa ukukuqonda, futhi umsebenzisi elula futhi "ulahleke". Lokhu eyinkimbinkimbi kuholela ukuqonda ukuthi yini ngempela akulona semininingwane okuningi lakhelwe imodeli phezulu. Isibonelo kuyinto database phezulu, ngaphezu umkhiqizo kakade kuchazwe "AyBiEm" inkampani "Oka" futhi Mieris (ukukhiqizwa Russian), kanye Data Edge Team-UP (kusuka corporations angaphandle).

izibonelo

egciniwe phezulu - ezihlukahlukene amazinga ehlukene lapho ubudlelwano zakhiwa. Schematically, kubukeka sengathi i-igrafu nabokhulumile. Isibonelo semininingwane phezulu - kunoma isiphi isimo isikhungo zokuphatha. Ngokwesibonelo, cabangela izinkondlo, esikoleni.

On ezingeni eliphezulu uzobe elise, "umholi we" Administration - Umqondisi. Ngo kuhanjiswa yayo amabombo othisha, othisha ikhanda kufanele - bothishela labasebentisa ukugada ukufana amakilasi. Ngo inombolo ngayinye parallel elingacacisiwe wabo, futhi ikilasi ngalinye nabafundi abaningana.

Isimiso esifanayo kungenziwa ebhaliwe, futhi ukuphathwa kwanoma yiphi corporation. Inhloko lenkampani noma ibhodi labaqondisi phezulu. Okulandelayo - ezandayo amayunithi ngamunye nesebenzela isakhiwo ayo. Zikhona izici ezivamile: eliphakeme kuyo yonke umnyango, nomsizi wakhe, nonobhala wakhe, eqinisweni, abasebenzi ehhovisi, nokunye.

Ukusetshenziswa kwama-computer

Kungase kube izicelo kakhulu. Isibonelo esimangalisayo base phezulu Idatha- kuyinto uhlelo lwefayela. Zonke ajwayelekile "-Windows Explorer" yakhiwe e ikhenela yesistimu yokusebenza "Vindous" Kungenxa isikimu enjalo, kanye nabanye abaphathi eziningi zamafayela.

senethiwekhi yeselula

kukhona:

• zingubudlelwane;
• phezulu;
• yolwazi inthanethi.

Sihlaleleni waphinda Sikhunjuzwa ngezigaba? Ngoba, ngokungafani zingubudlelwane senethiwekhi yeselula has a ukufana phezulu.

Isikhathi ukukhumbula izinhlobo ubudlelwano e yolwazi. Kunokuxhumana, "okukodwa-elilodwa", "okukodwa-abaningi" futhi "abaningi-kokuningi". Sinesithakazelo lakamuva. I database inethiwekhi kubonakala kanje: omunye owalandela node kungenzeka okhokho eziningana. Impahla yokuba engenanzalo engezelele ukulondolozwa. Singasho ukuthi yolwazi ephethwe yisigungu sesonto, inethiwekhi yolwazi ngokwabo kakade isibonelo lelo fa. Amadlozi kulokhu nje semininingwane phezulu, njengoba isimiso sokwakha kwenethiwekhi izakhiwo database uhlala ingashintshiwe.

Umkhakha futhi zingubudlelwane

Igama elithi "zingubudlelwane" livela egameni lesiNgisi elithi "isimo sengqondo". Njengoba kushiwo ekuqaleni kwalesi sihloko, avame uzwakalise in ifomu tabular. Kodwa esigabeni esandulele, sithi database phezulu Ungahlela futhi zokuxhumana, ingabe lokhu kusho ukuthi phakathi kwalezi zinhlobo ezimbili kukhona intambo noma ezicashile kubahlanganisa?

Yebo. Ngaphezu kokuba umuntu wokuqala futhi uhlobo lwesibili basabiza yolwazi, ngaphezu lesi sici kukhona ngento eyodwa. Ngokwesibonelo, database phezulu (inethiwekhi futhi ebalulekile nalo) ungaboniswa itafula. Iphuzu lapha alikho kwindlela ukwethula ulwazi kumsebenzisi wokugcina (lena umbuzo Ukusebenziseka esibonakalayo), kodwa lokho olwakhiwe kungasiphi isisekelo. Ngakho, i-ocacile ku imiNyango ababaphethe, nezinye amayunithi uzoqhubeka luboniswe esigabeni sabaphathi, kodwa ukuze kube lula kulethwa etafuleni.