我阅读了关于 3nf 的 wiki https://en.wikipedia.org/wiki/Third_normal_form
这是wiki给出的例子
Tournament Winners
Tournament Year Winner Winner Date of Birth
Indiana Invitational 1998 Al Fredrickson 21 July 1975
Cleveland Open 1999 Bob Albertson 28 September 1968
Des Moines Masters 1999 Al Fredrickson 21 July 1975
Indiana Invitational 1999 Chip Masterson 14 March 1977
它说 the non-prime attribute Winner Date of Birth is transitively dependent on the candidate key {Tournament, Year} via the non-prime attribute Winner
我认为功能依赖是
for two row X1 , X2 if X1.col1 = X2.col1 and
X1.col2 = X2.col2, then col1 -> col2
我无法理解获胜者的出生日期->获胜者(可能有相同的生日和相同的名字?)并且获胜者可以 -> 候选键 {Tournament, Year} 给定获胜者的名字 Al Fredrickson,它可能是 1998 年印第安纳邀请赛或得梅因大师赛 1999)
那么,它是如何得出结论的呢?