题目内容

一个关系模式为Y(X1，X2，X3，X4)，假定该关系存在如下函数依赖：X1←→X2，X1→X3，X1→X4，则该关系属于【18】。

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在关系模式R(D，E，G)中，存在函数依赖关系{E→D，(D，G)→E}则候选码为【7】，关系模式R(D，E，G)最高可以达到【8】。