Re: Surrogate Keys: an Implementation Issue

"Keith H Duggar" <duggar_at_alum.mit.edu> wrote in message news:1154503647.536338.77970_at_75g2000cwc.googlegroups.com...
> Brian Selzer wrote:
>> So, what you're saying is (1) that anything that can be
>> discussed must be distinguishable from every other thing
>> that can be or has been discussed, (2) that anything that
>> can be discussed must have at least one identifying
>> set of properties that is guaranteed to remain constant
>> throughout the discussion ...
>
> With regard to (2), my reading of JOG was that he said a
> tuple ("thing" as you call it) must have at least one
> identifying set of attributes ("properties" as you call
> them) that is guaranteed to remain /unique/ (not constant)
> with respect to the relation (ie there is always a key)
> throughout the discussion. Is this not correct?
>

No, he implied that the identifying set of attributes is guaranteed to remain constant.
This is clear from his responses, "the two states of the creature have the same DNA" and "If there were no common key, according to logic the two 'states' are wholly different things."

> [snip arguments about keys "changing" values]
>
> I don't think he ever said keys had to remain constant.
> Rather they must remain unique. So much of your
> argumentation above may not apply.
>
> -- Keith -- Fraud 6
>
Received on Wed Aug 02 2006 - 12:20:43 CEST