Re: Understanding candidate key and super key

"Low Yew Sing" <slasher_at_singnet.com.sg> wrote in message news:89r5dv$jgf$1_at_mawar.singnet.com.sg...

> hi,
> i have a question concerning candidate key and super key.
> For example ,
> if i have a office relation of lecturer, subject and telephone. A

Why? Is lecturer X allowed to talk only about subject Y on phone Z and must use phone Z' to talk about subject Y', if the table is as follows?

lecturer subject telephone

X         Y        Z
X         Y'       Z'

If this is the case, then (lecturer, subject) and (lecturer, telephone) are indeed candidate keys.

--
Joe Foster <mailto:jfoster_at_ricochet.net>  Space Cooties! <http://www.xenu.net/>
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