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发帖数: 61 | 1 suppose that R is given with attributes ( A,B,C,D,E,F) and
the FDs ( A-->BC, B-->E, CD-->EF)
i would like to know, for the superkey at here. why not can
just AD be the superkey. as i found the superkey's
defination : K is a superkey of a relation R iff K+ consists
of all attributes of R, i think ( A, D)+ = ( A,B,C,D, E ,F).
thus why not only the AD can be the superkey and has to plus
B and C.
thank you very much for your help. good day |
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