题目内容
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[主观题]
●Let R and S be the relation respection respectively:Relation R:A B C Relation S:B C D1 2
●Let R and S be the relation respection respectively:
Relation R:A B C Relation S:B C D
1 2 3 2 3 4
6 7 8 2 3 5
9 7 8 7 8 1
The number of tuples that the result of the expression R∞S(Here if natural join of relations R and S) is (69) .
(69) A.1
B.4
C.7
D.10
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