Onetsetsani kuti deta yoyenera yalowa
ZINTHU zosavomerezeka za NULL mu Microsoft SQL Server zimakulolani kufotokoza kuti chikhocho sichingakhale ndi zilembo za NULL . Mukamapanga chotsopanitsa chatsopano cha NULL m'ndandanda wachinsinsi, SQL Server imayang'anitsitsa zomwe zili m'ndandanda zamakono pazinthu zilizonse za NULL. Ngati ndimeyi pakali pano ili ndi malingaliro a NULL, chilengedwe chosemphana chimalephera. Popanda kutero, SQL Server imapanga chotsutsa cha NULL ndi zina ZONSE ZOKHUDZA kapena UPDATE malamulo omwe angachititse kukhalapo kwa NULL mtengo kulephera.
NULL ndi yosiyana ndi chingwe cha mtundu wa zero kapena zero. NULL imatanthauza kuti palibe kulowa mkati.
Kupanga CHINENERO CHA NULL
Pali njira zambiri zomwe mungapangire chosemphana ndi UNQQUE SQL Server. Ngati mukufuna kugwiritsira ntchito Transact-SQL kuti muwonjezere chosemphana ndi UNIQUE pa tebulo pomwepo, mungagwiritse ntchito mawu a ALTER TABLE, monga momwe tawonetsera apa:
ALTER TABLE
ALTER COLUMN SANKHA NULL
Ngati mukufuna kukambirana ndi SQL Server pogwiritsira ntchito zida za GUI, mukhoza kukhazikitsa chopanikizika cha NOT NULL pogwiritsa ntchito SQL Server Management Studio. Nazi momwemo:
- Tsegulani SQL Server Management Studio.
- Lonjezerani fayilo fayilo ya deta yomwe mukufuna kuimitsa.
- Dinani pa tebulo komwe mukufuna kuwonjezera zovutazo ndikukani Pangani.
- Sungani bukhu la NOTELE la zolemba zomwe mukufuna kuti musakhale nazo ZINTHU zosavuta.
Ndizo zonse zomwe zikupangidwira zolemba za NOT NULL mu Microsoft SQL Server!