【单选题】【消耗次数：1】
用于实现实体完整性约束的是（ ）。
①
PRIMARY KEYCHECKDEFAULT
②
UNIQUE
参考答案：
复制
纠错
相关题目
【简答题】
关系模型的三类完整性约束是实体完整性、参照完整性和[填空1]。
【简答题】
参照完整性规则是对[填空]的约束。
【简答题】
在Visual FoxPro中通过建立主索引或候选索引来实现[填空1]完整性约束。
随机题目
【简答题】
韩愈诗歌[填空]，白居易诗歌平易，在诗歌创作上表现出两个极端。
【单选题】
Doctor: ____ Patient: I’ve caught a bad cold and got a sour throat.?
①
What seems to be the problem? ?
②
?Do you have anything to declare, sir??
③
Good morning. May I help you? ?
④
How have you been getting along recently??
【单选题】
Have a nice weekend! - ____.
①
The same as you
②
The same to you
③
You have it, too
④
You do, too
【单选题】
The two families____ up through the marriage of a daughter and a son. ?
①
linked ?
②
closed ?
③
separated ?
④
attached.?
【单选题】
____ he tried his best , he still failed the examination.
①
Although
②
Even although
③
However
④
Because
【单选题】
The research results show that the earth goes a little faster ____ it is closer to the sun.
①
when
②
so that
③
than
④
as if
【单选题】
As she matured as an artist, she _____ realize that “all artists are a product of their culture.”
①
came to
②
kept to
③
took to
④
went to
【单选题】
I have nothing to say____ your complaints.
①
as a result of
②
in addition to
③
with regard to
④
on behalf of