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Re: Basic question?What 's the key if there 's no FD(Functional Dependencies)?

From: Brian Selzer <brian_at_selzer-software.com>
Date: Wed, 01 Nov 2006 14:40:03 GMT
Message-ID: <7l22h.18849$TV3.2196@newssvr21.news.prodigy.com>

<saturnlee_at_yahoo.com> wrote in message
news:1162158876.794350.29460_at_f16g2000cwb.googlegroups.com...
> I have a basic question.
> Suppose there are 3 attributes: A,B and C.
> And there are no FD(trivial and non trivial )
>
> What 's the key for it? ABC or nothing???
>

A relation with at least one attribute *ALWAYS* has at least one FD. Here are some of them for your example:

{ABC} --> A
{ABC} --> B
{ABC} --> C
{ABC} --> {ABC}

Note that all of the FD's are trivial. Received on Wed Nov 01 2006 - 08:40:03 CST

Original text of this message

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