Zogwira Ntchito Zothandizira Pewani Kufotokozera Deta
Kudalira kogwira ntchito m'databata kumathandiza kuti pakhale zovuta pakati pa zikhumbo. Izi zimachitika pamene chidziwitso chimodzi mu chiyanjano chimapanga chizindikiritso china. Izi zikhoza kulembedwa A -> B zomwe zikutanthauza kuti "B ikudalira A. Izi zimatchedwanso kudalira deta .
Mu ubale uwu, A amatsimikizira kufunika kwa B, pamene B ikudalira A.
Chifukwa chiyani ntchito yogwira ntchito ndi yofunikira mu Database Design
Kugwira ntchito mogwira ntchito kumathandiza kutsimikizira kufunika kwa deta.Kuwona tebulo Ogwira ntchito omwe amalemba zinthu monga Social Security Number (SSN), dzina, tsiku lobadwa, aderese ndi zina zotero.
Chikhumbo SSN chidzapindulitsa kufunika kwa dzina, tsiku la kubadwa, adiresi ndi zina zabwino, chifukwa nambala ya chitetezo cha anthu ndi yapadera, pamene dzina, tsiku la kubadwa kapena adiresi silingakhale. Titha kulemba izi monga izi:
SSN -> dzina, tsiku la kubadwa, adilesi
Choncho, dzina, tsiku la kubadwa ndi adiresi likugwira ntchito kudalira SSN. Komabe, mawu otsutsa (dzina -> SSN) si oona chifukwa antchito angapo akhoza kukhala ndi dzina lomwelo koma sadzakhala nawo SSN yomweyo. Ikani njira yina, yowonjezera, ngati tidziwa kufunika kwa malingaliro a SSN, tingapeze phindu la dzina, tsiku la kubadwa ndi adiresi. Koma ngati ife tidziwa phindu la dzina lokha, sitingazindikire SSN.
Mbali ya kumanzere ya kudalira kogwira ntchito kungaphatikizepo zifukwa zingapo. Tiye tikuti tili ndi bizinesi ndi malo ambiri. Tikhoza kukhala ndi gome Wogwira ntchito ndi zotsatira za ogwira ntchito, udindo, dipatimenti, malo ndi bwana.
Wogwira ntchitoyo amadziwa malo omwe akugwira ntchito, kotero pali kudalira:
wogwira ntchito -> malo
Koma malo angakhale ndi abwana angapo, kotero ogwira ntchito ndi dipatimenti pamodzi amadziwitsa abwana:
wogwira ntchito, dipatimenti -> manager
Kugwira Ntchito Kumadalira ndi Kukhazikitsa
Kudalira kugwira ntchito kumaphatikizapo zomwe zimatchedwa deta normalization , zomwe zimatsimikizira kudalirika kwa deta komanso zimachepetsanso ziphuphu. Popanda kuzindikiritsa, palibe chitsimikizo kuti deta mudatabata ndi yolondola komanso yodalirika.