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Student(StdNo,StdName,appointNo,timing,advisor)
和功能的依賴關係是:
StdNo->StdName
StdNo,appointNo->Timing,advisor
Timing->appointNo
通過正火2NF我得到:
R1(stdNo,appointNo,Timing,advisor)
R2(stdNo,StdName)
我覺得這已經是3NF。但我在減少BCNF方面遇到了麻煩。
對於BCNF,我認爲R1關係違反了BCNF作爲Timing-> appointNo和Timing不是超級關鍵。我如何減少BCNF?