Izinqununu zikhomba amanani anikwe ezinye izimfanelo
I-determinant etafuleni lesitatimende yimbonakaliso engasetshenziselwa ukunquma amanani anikwe ezinye izimfanelo emgqeni ofanayo. Ngale ncazelo, noma yikuphi ukhiye oyinhloko noma ukhiye wokugqoka kuyinquma, kodwa kungase kube nezinqumo ezingezona eziyinhloko noma ezikhethiwe.
Isibonelo, inkampani ingasebenzisa ithebula ngezici , , no .
| I-Employee_id | Igama | Isibongo | Usuku lokuzalwa |
|---|
123
| Megan | Brown | 01/29/1979 |
| 234 | UBen | Wilder | 02/14/1985 |
| 345 | Megan | Chowdery | 2/14/1985 |
| 456 | Charles | Brown | 07/19/1984 |
Kulokhu, insimu inquma amasimu amathathu asele. Amasimu egama asinqumi ngoba inkampani ingaba nabasebenzi ababelana ngegama elifanayo noma lokuqala. Ngokufanayo, field ayinqumi noma izinkampani igama ngoba abasebenzi bangabelana ngosuku lokuzalwa olufanayo.
Ubudlelwane obunqunyiwe bamaKhisimusi esisekelo
Kulesi sibonelo, iyinhloko ecacile, ukhiye wokukhetha, futhi futhi ukhiye oyinhloko. Kuyinto eyinhloko yokhetho ngoba lapho yonke i-database isesha 234, umugqa oqukethe imininingwane ngo-Ben Wilder ubonakala futhi akukho enye irekhodi eboniswayo. Omunye ukhiye ozobhalwa ukhetho uma kwenzeka ucwaninga le database ngolwazi kumakholomu amathathu; , no , eliphinde lithole umphumela ofanayo.
I- iyisihluthulelo esiyinhloko ngenxa yazo zonke izinhlanganisela zamakholomu angasetshenziswa njengokhiye wokukhetha, yikholomu elula ongayisebenzisa njengento ebaluleke kakhulu kuletafula.
Futhi, i- iqinisekisiwe ukuthi iyingqayizivele kuletafula, kungakhathaliseki ukuthi bangaki abanye abasebenzi abakhona, ngokungafani nolwazi kwamanye amakholomu.