唯一不为空和零
unique not null and zero
我是 SQL 的新手,我在列中创建了一个唯一键。现在我想更改不允许任何空值或零值的列。
我试过这样做
ALTER TABLE sales ALTER COLUMN VerificationCode VARCHAR NOT NULL
然而,这会产生以下错误:
The object 'UQ_Sales_VerificationCode' is dependent on column 'VerificationCode'.
Msg 4922, Level 16, State 9, Line 74
ALTER TABLE ALTER COLUMN VerificationCode failed because one or more objects access this column.
尝试先删除约束,然后 更改 table 列:
ALTER TABLE sales DROP CONSTRAINT UQ_Sales_VerificationCode
然后做
ALTER TABLE sales ALTER COLUMN VerificationCode VARCHAR NOT NULL
我是 SQL 的新手,我在列中创建了一个唯一键。现在我想更改不允许任何空值或零值的列。
我试过这样做
ALTER TABLE sales ALTER COLUMN VerificationCode VARCHAR NOT NULL
然而,这会产生以下错误:
The object 'UQ_Sales_VerificationCode' is dependent on column 'VerificationCode'. Msg 4922, Level 16, State 9, Line 74 ALTER TABLE ALTER COLUMN VerificationCode failed because one or more objects access this column.
尝试先删除约束,然后 更改 table 列:
ALTER TABLE sales DROP CONSTRAINT UQ_Sales_VerificationCode
然后做
ALTER TABLE sales ALTER COLUMN VerificationCode VARCHAR NOT NULL