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如果我有一个模式说R={A,B,C,D}和功能依赖关系说{B->C, D->A}我的候选键集是{B,D}or{BD}吗?
R={A,B,C,D}
{B->C, D->A}
{B,D}
{BD}
如果 B 是候选键,则您必须能够从问题中给出的函数中派生这些函数依赖关系。
你能做到吗?