Re: the relational model of data objects *and* program objects

From: FrankHamersley <FrankHamersleyZat_at_hotmail.com>
Date: Thu, 14 Apr 2005 15:18:50 GMT
Message-ID: <uRv7e.11480$5F3.6845@news-server.bigpond.net.au>

erk wrote:
> Kenneth Downs wrote:

>>Frank_Hamersley wrote:
>>>Chalk my vote alongside Kenneths!   When you consider temporal aspects
>>>then "Extended" does indeed become data if the DBMS does not retain
>>
>>          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>
>>>temporally appropriate values for the data and the function (business
>>>rule) that can be reliably presented when required by all and sundry.
>> 
>> I have been seeking a precise way to state this, some kind of bumper
>> sticker
>> phrase that moves derived data from the status of red-headed
>> stepchild to
>> heir to the throne.  So far nothing :(

>
> What is derived and what is data depends on the application, doesn't
> it? In that case, something in the specification needs to state which
> is "extended" and which is "real data." I fail to grasp the need for
> and nature of some "transformation" from "extended" to "data."

Not sure what you meant by the last sentence (its late here!).

>>The idea is that the extended values are actually more true than their
>>antecedents.  A seller and a buyer haggle over the price of widgets,which
>>are 1.00 each.  The seller offers 10 widgets at 90 cents each, they
>>eventually settle on 15 widgets for 13.00, at which point the per-widget
>>price is of only historical interest.

>
> Again, given that reports can be run against data of purely "historical
> interest," how is storing this any different than storing
> "non-historical data"?
>
> Also, if history is important (and it is), why bother storing values
> when you can store the history of the functions/calculations? And
> you'll still need a way of specifying which data should be updated when
> the function changes, versus those which are "first-rate" values that
> are just stored (and thus indistinguishable in my mind from "data" as
> such).

Taking Kenneths example - as the widget salespersons manager when I ask for a report on how much discount (from the published price) a particular client has negotiated I need both numbers.

>>Two points here.  The "caching" idea is very strong, perhaps that is the
>>bumper-sticker slogan?
>>
>>Second: "theory".  Why do we allow a body of abstract mathematics to hold
>>the lofty title "theory" when it does not exist to serve human needs?

>
> Of course it does. And what theory are you talking about? To quote
> Inigo Montoya from "The Princess Bride": "I do not think that word
> means what you think it means."

Maybe the bumper sticker is "Your best practice is another's failed project". I have no beef with either the theorist or the pragmatist - but only if they do not preach dogmatically that the other is wrong wrong wrong!

Cheers, Frank. Received on Thu Apr 14 2005 - 10:18:50 CDT