Zovuta za UNIQUE mu Microsoft SQL Server

Ubwino Wogwiritsa Ntchito Zopinga Zopanda Pakati pa Zopinga Zowunika Kwambiri

Pogwiritsa ntchito zovuta za UNIQUE, olamulira a SQL Server amatsimikizira kuti chikhocho sichingakhale ndi zilembo zosiyana. Mukamapanga zovuta zatsopano za UNIQUE, SQL Server imayang'anitsa ndime yomwe ili mu funso kuti ione ngati ili ndi mfundo zofanana. Ngati gome liri ndi zolembedwa zomwe zisanachitikepo, lamulo lachilengedwe lokhazikika limalephera. Mofananamo, mutakhala ndi chosemphana ndi UNIQUE pa chigawo, kuyesa kuwonjezera kapena kusintha chidziwitso chimene chikhoza kuchititsa kuti pakhale palibenso akulephera.

Chifukwa Chogwiritsira Ntchito Zopinga Zokha

Chosemphana ndi UNIQUE ndi chofunikira chachikulu zimagwirizanitsa zokhazokha, koma nthawi zina zovuta za UNIQUE ndizosankha bwino.

• Gwiritsani ntchito chosemphana ndi UNIQUE pamene mukufuna zovuta zambiri pa tebulo. Mukhoza kungowonjezera kiyi imodzi yoyamba pa tebulo.
• Gwiritsani ntchito chosemphana ndi UNIQUE pamene chilolezo chiloleza kuti zikhale zosayenera. Zovuta zachinsinsi zazikulu zingathe kuphatikizidwa pazitsulo zomwe sizimalola kuti chikhalidwe chisawonongeke.

Kukhazikitsa Kumbali UNIQUE

Pali njira zambiri zomwe mungapangire chosemphana ndi UNQQUE SQL Server. Ngati mukufuna kugwiritsa ntchito Transact-SQL kuti muwonjezere chosemphana ndi UNIQUE pa tebulo lomwe liripo, mungagwiritse ntchito mawu a ALTER TABLE, monga momwe tawonetsera pansipa:

ALTER TABLE ADDIZANI CONSTRAINT UNIQUE ()

Ngati mukufuna kukambirana ndi SQL Server pogwiritsira ntchito zida za GUI, mukhoza kukhazikitsa chosemphana ndi UNIQUE pogwiritsa ntchito SQL Server Management Studio . Nazi momwemo:

1. Tsegulani SQL Server Management Studio .
2. Lonjezerani fayilo foda ya deta yomwe mukufuna kupanga chosemphana.
3. Dinani pa tebulo komwe mukufuna kuwonjezera zovutazo ndi dinani Kulinganiza .
4. Mu Table Designer menyu, dinani Zolemba / Zowonjezera .
5. Mu bokosi la Ma Index / Keys, dinani Add .
6. Sankhani Chinthu Chachidwi pa Mtundu Wotsitsa.

Zowonongeka za UNIQUE vs. Zolemba za UNIQUE

Pakhala chisokonezo chokhudza kusiyana pakati pa UNIQUE contrainte ndi index UNIQUE. Ngakhale mutagwiritsa ntchito malamulo osiyana-siyana a Transact-SQL kuti muwapange (ALTER TABLE ... LANDANI CONSTRAINT pa zovuta ndi CREATE UNIQUE INDEX kwa inde), ali ndi zotsatira zofanana, makamaka. Ndipotu, mukamapanga zovuta za UNIQUE, kwenikweni zimapanga ndondomeko ya UNIQUE pa tebulo. Ndizodabwitsa kuzindikira kuti pali kusiyana kosiyana:

• Mukamapanga ndondomeko, mukhoza kuwonjezera zina zomwe mungapange pa lamulo lachilengedwe.
• Mndandanda wogonjetsedwa ndi UNIQUE chotsutsana ungagwiritsidwe ntchito ngati chinsinsi chachilendo .