试题与答案

在关系的基本运算中,下列属于专门关系运算的是A.选择、排序 B.选择、投影 C.并、

题型:单项选择题

题目:

在关系的基本运算中,下列属于专门关系运算的是

A.选择、排序

B.选择、投影

C.并、差、交

D.联接、笛卡儿积

答案:

参考答案:B

解析:【解析】关系的基本运算可以分为两类:传统的集合运算和专门的关系运算。传统的集合运算包括并、差、交等,专门的关系运算包括选择、投影和联接。

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题型:填空题



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