●Let R and S be the relation respection respectively：Relation R:A B C Relation S:B C D1 2 3 2 3 46 7 8 2 3 59 7 8 7 8 1The number of tuples that the result of the expression R∞S(Here if natural join of relations R and S) is (69) ．(69) -题库考试答案搜索网

●Let R and S be the relation respection respectively：Relation R:A B C Relation S:B C D1 2 3 2 3 46 7 8 2 3 59 7 8 7 8 1The number of tuples that the result of the expression R∞S(Here if natural join of relations R and S) is (69) ．(69)

单选题

2022-01-04 01:08

A、1
B、4
C、7
D、10

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正确答案

B

试题解析

【解析】译文：关系R和S分别是关系R:A B C,关系S:B C D。表达式R∞S(这里式R、S的自然连接)的结果的元组个数为4。

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