Re: Relation Schemata vs. Relation Variables
From: paul c <toledobythesea_at_oohay.ac>
Date: Thu, 24 Aug 2006 23:42:59 GMT
Message-ID: <7QqHg.452409$Mn5.125427_at_pd7tw3no>
>
> A candidate key does not identify a tuple. A candidate key is a
> constraint on a relvar and not on a tuple.
Date: Thu, 24 Aug 2006 23:42:59 GMT
Message-ID: <7QqHg.452409$Mn5.125427_at_pd7tw3no>
Bob Badour wrote:
> paul c wrote:
>
>> paul c wrote: >> ... >> >>> >>> PMFJI, I would say that the VALUE of a candidate key identifies one >>> and only one tuple FOREVER! >> >> >> Stupid me, I have to take part of that back - the value of a candidate >> key obviously could identify several tuples but I still think that >> would hold forever. Might have been better to say the value of a >> candidate key identifies a tuple regardless of time.
>
> A candidate key does not identify a tuple. A candidate key is a
> constraint on a relvar and not on a tuple.
p Received on Fri Aug 25 2006 - 01:42:59 CEST