最美的时光.
4.2.5
From Augmentation rule of Functional Dependency,
given
B -> M (B=Baby, M=Mother)
then
BND -> M (N=Nurse, D=Doctor)
Hence we can just put an arrow entering mother.
a) Put an arrow entering entity set Mothers for the simplest solution (As in fig. 4.4, where a multi-way relationship was allowed, even though Movies alone could identify the Studio). However, we can display more accurate information with below figure.
精品
