Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation
From: Jon Heggland <jon.heggland_at_idi.ntnu.no>
Date: Thu, 03 May 2007 14:53:35 +0200
Message-ID: <f1cm3g$l75$1_at_orkan.itea.ntnu.no>
>> I don't think the semantics of key updates is as clear-cut as you think,
>> though. It may seem intuitively obvious that when you update the sole
>> key of a "Person" relvar, you are still talking about the same person
>> (speaking loosely). But this is entity thinking, which is fuzzy, and
>> dangerous to mix with relational theory. I am skeptical as to whether
>> this notion of "sameness" can be formalised, and generalised to the less
>> obvious cases.
>
> I don't think the semantics of key updates is even relevant.
Date: Thu, 03 May 2007 14:53:35 +0200
Message-ID: <f1cm3g$l75$1_at_orkan.itea.ntnu.no>
Brian Selzer wrote:
> "Jon Heggland" <jon.heggland_at_idi.ntnu.no> wrote in message > news:f1c26e$9nk$2_at_orkan.itea.ntnu.no...
>> I don't think the semantics of key updates is as clear-cut as you think,
>> though. It may seem intuitively obvious that when you update the sole
>> key of a "Person" relvar, you are still talking about the same person
>> (speaking loosely). But this is entity thinking, which is fuzzy, and
>> dangerous to mix with relational theory. I am skeptical as to whether
>> this notion of "sameness" can be formalised, and generalised to the less
>> obvious cases.
>
> I don't think the semantics of key updates is even relevant.
I think it is crucial if you want to claim that relation-based TCs are less powerful/expressive than tuple-based TCs. And ... Bah. This is just a rehash of the "Relation Schemata vs. Relation Variables" thread. Anyone interested in my thoughts can read that one.
-- JonReceived on Thu May 03 2007 - 14:53:35 CEST