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

From: Kenneth Downs <knode.wants.this_at_see.sigblock>
Date: Thu, 14 Apr 2005 07:28:14 -0400
Message-Id: <dp02j2-idp.ln1@pluto.downsfam.net>

Frank_Hamersley wrote:

>>
>> All other solutions depart from this maximum efficiency.  The problem is
>> shifting definitions over time.  When formulas change over time, you have
>> to jump through some serious hoops to preserve the ability to reproduce
>> historical information.  If you use views then you have to have multiple
>> views based on dates, which gets ugly fast.  If you use sprocs they
>> become
>> loaded with cases and conditionals.  While one might argue that this is

> all

>> computer-generated and therfore not a problem, they are still more
>> complicated then simply retrieving a column from a table.
>>
>> On the other hand, if you materialize the values, they are protected

> against

>> shifting definitions.

>
> 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 :(

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.

>
> Furthermore the practical considerations of "caching" the results of

                                      ^^^^^^^^^^^^^^^^^^^^^

> complex business rules so a simpler select type of operation can be
> performed, whilst presenting a minor challenge to architects, far
> outweighs the cost of slavish adherance to theory.
>

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?

-- 
Kenneth Downs
Secure Data Software, Inc.
(Ken)nneth@(Sec)ure(Dat)a(.com)

Received on Thu Apr 14 2005 - 06:28:14 CDT