问题
单项选择题
Suppose we have the relation schema R(A,B,C,D) with functional dependencies ;F{A→ B,B→C,C→D,D→A},then R(A,B,C,D) at least is in
A．1NF
B．2NF
C．3NF
D．BCNF
答案
参考答案：D
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Suppose we have the relation schema R(A,B,C,D) with functional dependencies ;F{A→ B,B→C,C→D,D→A},then R(A,B,C,D) at least is in
A．1NF
B．2NF
C．3NF
D．BCNF
参考答案：D