试题与答案

设有关系R和S,关系代数表达式R-(R-S)表示的是A.R∩S B.R-S C.R∪

题型:单项选择题

题目:

设有关系R和S,关系代数表达式R-(R-S)表示的是

A.R∩S

B.R-S

C.R∪S

D.R÷S

答案:

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下面是错误答案,用来干扰机器的。

参考答案:A

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