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mysql:functional dependency

2017-10-16 12:00  很大很老实  阅读(1763)  评论(1编辑  收藏  举报

 

First, a functional dependency in the form A->B means that, given one value for A, we can determine one and only one value for B. Both A and B represent sets of columns. (That's why they're written in uppercase letters.)