Re: 2nd Normal Form Question
From: David Portas <REMOVE_BEFORE_REPLYING_dportas_at_acm.org>
Date: Fri, 8 Feb 2008 22:48:38 -0000
Message-ID: <QOSdncMFYr7bQTHanZ2dnUVZ8rGdnZ2d_at_giganews.com>
Date: Fri, 8 Feb 2008 22:48:38 -0000
Message-ID: <QOSdncMFYr7bQTHanZ2dnUVZ8rGdnZ2d_at_giganews.com>
"paul c" <toledobythesea_at_oohay.ac> wrote in message
news:Kp3rj.6645$Ly.6410_at_pd7urf1no...
> David Portas wrote:
> ...
>> Here's a counter example. PatientId is the candidate key but the relation
>> is not in 2NF. This is an unusual case but I don't think it should be
>> ignored.
>>
>> Pregnancies {PatientId, Gender, DueDate}
>>
>> FDs:
>> {PatientId} -> {DueDate}
>> {} -> {Gender}
>>
>
> If you have {} -> {Gender} don't you also have {PatiendId} -> {Gender,
> DueDate} ?
Yes.
-- David PortasReceived on Fri Feb 08 2008 - 23:48:38 CET