未分类题

下面两题是基于“学生-选课-课程”数据库中的三个关系:
S(S#,SNAME,SEX,AGE),SC(S#,C#,GRADE),C(C#,CNAME,TEACHER)
若要求查找选修“数据库技术”这门课程的学生姓名和成绩,将使用关系
D.S、SC和C

A.S和SC
B.SC和C
C.S和C

【参考答案】

D
解析：课程名只有关系C中有,学生姓名只有关系S中有,成绩只有关系SC中有,所以三个关系都得用到。
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A.B.
C.
D.
E.
F.
G.
H.'
I.
J.
K.
【C1】
A.grasp
B.grip
C.hold
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