If a unique constraint is defined on column COL1 of table TAB1, what are the characteristics of COL1?（）
- A、COL1 will accept NULL values and can be referenced in another table's foreign key specification.
- B、COL1 will not accept NULL values and cannot be referenced in another tables foreign key specification.
- C、COL1 will not accept NULL values and can be referenced in another tables foreign key specification.
- D、COL1 will accept NULL values and cannot be referenced in another tables foreign key specification.
正确答案:C
答案解析:有
微信扫一扫手机做题