Chifungulo chachilendo chimatsegula chitseko ku dziko lonse la deta
Anthu ogwiritsa ntchito mafashoni amagwiritsira ntchito makiyi pogwiritsa ntchito zida zogwirizana. Zina mwazimenezi ndizo mafungulo oyambirira ndi mafungulo akunja. Mndandanda wachinsinsi wachinsinsi ndi munda m'mabuku oyanjana omwe amagwirizana ndi chinsinsi chofunikira cha tebulo lina. Kuti timvetsetse momwe zingwe zakunja zikugwirira ntchito, tiyeni tiwone bwinobwino lingaliro la malo osungirako zinthu.
Zina Zomwe Zina Zogwirizana Zosonkhana
Mu deta yolumikizana, deta imasungidwa m'matawuni okhala ndi mizere ndi zigawo, zomwe zimapangitsa kuti zifufuze kufufuza ndikugwiritsa ntchito. Pali masamu akuluakulu pambuyo pa lingaliro lothandizira (relational algebra, loperekedwa ndi EF
Codd ku IBM mu 1970), koma izi siziri mutu wa nkhaniyi.
Zolinga zenizeni (ndi osakhala masamu), malo osungirako zinthu amalemba deta "yokhudzana" mumzere ndi mizere. Kuwonjezera-ndipo apa ndi pamene zimakhala zosangalatsa-zolemba zambiri zakonzedwa kotero kuti deta patebulo limodzi likhoza kulumikiza deta mu tebulo lina. Mphamvu iyi yolenga ubale pakati pa matebulo ndi mphamvu yeniyeni ya deta yolumikizana.
Kugwiritsa Ntchito Zowona Zachilendo
Ma tebulo ambiri, makamaka omwe ali m'mabuku akuluakulu, ovuta, ali ndi mafungulo apamwamba. Ma tebulo omwe apangidwa kuti athe kupeza matebulo ena ayenera kukhala ndi makiwo akunja.
Kuti mugwiritse ntchito ndondomeko yotchulidwa kawirikawiri ya Northwinds, apa pali ndondomeko yochokera ku Gulu la Zamtundu:
| ProductID | Zamalonda | CategoryID | QuantityPerU | Mtengo wagawo |
|---|---|---|---|---|
| 1 | Chai | 1 | Mabokosi 10 x matumba 20 | 18.00 |
| 2 | Kusintha | 1 | 24 - 12 oz mabotolo | 19.00 |
| 3 | Sirave Yowoneka | 2 | 12 - 550 ml mabotolo | 10.00 |
| 4 | Mtsinje wa Anton wa Cajun Seasoning | 2 | 48 - 6 oz mitsuko | 22.00 |
| 5 | Gumbo Mix ya Chef Anton | 2 | 36 mabokosi | 21.35 |
| 6 | Agogo a Boysenberry Akufalikira | 2 | 12 - 8 oz mitsuko | 25.00 |
| 7 | Amalonda a Amal Bob's Peanic Zouma | 7 | 12 - 1 lb pkgs. | 30.00 |
Chigawo cha ProductID ndichinsinsi chachikulu cha tebulo ili. Amapatsa chidziwitso chapadera kwa mankhwala onse.
Tebulo ili lilinso ndichinsinsi chachilendo chachilendo, CategoryID . Chogulitsa chirichonse mu Pulogalamu yamalumikizi chikugwirizana ndi kulowa mu Gawo la table lomwe limatanthawuza gulu la mankhwalawa.
Tawonani izi kuchokera mudongosolo ladongosolo lachinsinsi:
| CategoryID | CategoryName | Kufotokozera |
|---|---|---|
| 1 | Zakudya | Zakumwa zofewa, khofi, teas, mowa, ndi ales |
| 2 | Zikumbutso | Zakudya zokoma ndi zokoma, zimasintha, zimafalikira, ndi nyengo |
| 3 | Kugwirizana | Desserts, candies, ndi zokoma |
| 5 | Zakudya Zamakaka | Zakuchi |
Gulu la CategoryID ndichinsinsi choyambirira cha mzerewu. (Alibe chinsinsi chachilendo chifukwa sichifunikira kufikira tebulo lina. Mwachitsanzo, mankhwala a Chai amapatsidwa gawo lakuti "Beverages", pamene Aniseed Syrup ali m'gulu la Condiments.
Kuyanjanitsa kotereku kumapanga njira zambiri zomwe mungagwiritsire ntchito ndikugwiritsanso ntchito deta mu deta yolumikizana.