Qiniseka ukuthi inani elifanele ledatha lifakiwe
IZINQINISO ze-NULL ku-Microsoft SQL Server ikuvumela ukuba ucacise ukuthi ikholomu kungenzeka ingabi namanani we-NULL . Uma udala isimiso esisha se-NOT NULL kukholomu yedatha, i-SQL Server ihlola okuqukethwe kwamanje ikholomu nganoma yimaphi amanani we-NULL. Uma ikholomu okwamanje iqukethe amanani we-NULL, indalo yokucindezela ihluleka. Ngaphandle kwalokho, i-SQL Server ingeza inkinobho ye-NULL kanye nanoma yikuphi ukulalelwa kwe-INSERT noma OKUPHAKATHI okuzokwenza ukuthi kube khona inani le-NULL elihlulekayo.
I-NULL ihlukile kuhlu lwezinhlamvu zero noma zero. I-NULL isho ukuthi akukho okufakwayo okwenziwe.
Idala isikhala esingu-NOT NULL
Kunezindlela eziningi ongakha ukucindezeleka okungavunyelwe ku-SQL Server. Uma ufisa ukusebenzisa i-Transact-SQL ukwengeza isibopho esingavumelekile kuthebula elikhona, ungasebenzisa isitatimende se-ALTER TABLE, njengoba kuboniswe ngezansi:
ALTER ITHEBULA
I-ALTER COLUMN AKUNYE NULL
Uma ukhetha ukusebenzisana ne- SQL Server usebenzisa amathuluzi we-GUI, ungase futhi udale ingcindezi ye-NULL engekho ngokusebenzisa i-SQL Server Management Studio. Nansi indlela:
- Vula SQL Server Management Studio.
- Nweba ifolda yamathebula wedatha lapho ufisa ukudala imithintelo.
- Chofoza ngakwesokudla itafula lapho ufisa ukungeza khona ukucindezela bese uchofoze Design.
- Hlola ibhokisi lokuhlola le-NULL yekholomu (ama) okufisa ukungabi NOMA imithi noma i-NULL.
Yilokho kuphela okukhona ukudala izinkinga ze-NULL ku-Microsoft SQL Server!