Re: SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS

On 22/09/2010 6:52 AM, Brian wrote:
> On Sep 22, 7:10 am, Erwin<e.sm..._at_myonline.be> wrote:
>> On 22 sep, 03:31, Brian<br..._at_selzer-software.com> wrote:
...
>>> Constraints are a matter of semantics--that is, what the data means.
>>
>> And what the data means is the logical conjunction of the propositions
>> that the tuples represent, or in my abstract example, "P(t1) AND
>> P(t2)", and "P(t3) AND P(t4)", respectively, and this regardless of
>> what the P() is.
>>
>> Nothing less, and most certainly nothing more. And I do not need to
>> specify the predicate for that claim to be true.
>>
>> Meaning that the transition itself, is not part of the semantics of
>> the database. Meaning that transition constraints are, contrary to
>> what you claim, NOT about semantics. And therefore NOT about business
>> rules either.
>>
>> Also meaning that if you have one possible transition from "P(t1) AND
>> P(t2)" to "P(t3) AND P(t4)" that gets rejected, and another one from
>> "P(t1) AND P(t2)" to "P(t3) AND P(t4)" that gets accepted, then that
>> means that your model is driven by something more than merely
>> semantics, and that in turn means that your model is flawed.- Hide quoted text -
>>
>> - Show quoted text -

> ... Your argument above is lacking because it
> doesn't take into account that since P(t1) and P(t3) were judged to be
> true at different times, P(t1) and P(t3) can mean the same thing at
> different times, or different things at different times.  ...

Heh, here we go again, more attacking mutant tuples, but thanks for a great example of undersimplification. A database where two different propositions mean the same thing (no matter whether at the same time or at different times) is seriously nonsensical, likely laughable even to a layman, possibly dangerously unmaintainable and certainly over-priced. Redundant, anyone? Received on Wed Sep 22 2010 - 18:46:37 CEST