Indlela Yokuthola Idokhumenti Yedatayela Ukusebenzisa i-Superkey

I-superkey yisici esingasetshenziselwa ukukhomba irekhodi lesisekelo

I-superkey ingabodwa noma inhlanganisela yezimfanelo ezingasetshenziswa ukukhomba ngokukhethekile irekhodi lemininingwane. Ithebula lingase libe nezinhlanganisela eziningi ezidala ama-superkeys.

Isibonelo Esihle

Ithebula elinamasimu , , ne-, isibonelo, linama-superkeys amaningi. Ama-superkeys amathathu angu-, ne-SSN, Igama>.

Njengoba ubona, amakholomu we- ne-Age> anezinhlobonhlobo eziningi ngolwazi olufanayo. Ngenkathi ikholomu ye- ingasetshenziswa ukuthola umuntu, isandiso sefoni singashintshwa.

Izinhlobo ze-Superkeys

Kulabo ababalulwe etafuleni elingenhla, kuphela i- iyinhloko yokhetho , okuyi-subset ekhethekile ye-superkeys esebenzisa inani elilinganiselwe lezimfanelo zokukhomba irekhodi kuphela. Amanye amakholomu aqukethe ulwazi olungadingekile ukuthola amarekhodi.

I-SSN> ingabuye ibhekiswe njengokhiye obuncane noma i-superkey encane ngoba iqukethe inani elincane lemininingwane edingekayo ukukhomba irekhodi ngalinye. Ngaphakathi kwemigqa efanayo, ukhiye oyinhloko ungabuye ube yi-superkey kanye nesikhiye esincane ngoba kufanele unikeze kuphela irekhodi, futhi kufanele kungavamile uma kwenzeka, ushintshe.

Uma ithebula lingenalo ikholomu bese umqashi angakha izinombolo zomsebenzi ukuze akwazi ukubona abantu.

Amanani omsebenzi omusha ayezobizwa ngokuthi ukhiye oyinhloko wokuzikhethela. Lesi sikhiye esiyisisekelo sokuqala sizophinde sibe njenge-superkey.