Re: A pk is *both* a physical and a logical object.

From: paul c <toledobythesea_at_oohay.ac>
Date: Wed, 18 Jul 2007 15:54:37 GMT
Message-ID: <1Jqni.129238$NV3.92140@pd7urf2no>

Brian Selzer wrote:
> "David Cressey" <cressey73_at_verizon.net> wrote in message
> news:Cmhni.6545$Gx5.2883_at_trndny02...

...

>>The table deosn't tell you whether a widget was moved,  or whether a 
>>widget
>>was removed, and another one inserted somewhere else.
>>

>
>
> You're proving my point: it can't be determined whether it is a different
> individual or the same individual because the key value is not rigid. ...

Regarding rigidity, I would say that if we ever admit a value to be not rigid, further investigation becomes pointless and we are lost.

p Received on Wed Jul 18 2007 - 10:54:37 CDT