Re: Reflections of a beautiful mind... Fundamental principle: Separation of Concerns

Bob Badour wrote:

> Frank Hamersley wrote:

>>> For instance, the third principle would seem to argue strongly 
>>> against null and n-vl.

> 
> You have lost me here. How have they introduced a cominatorial
> explosion of special cases?

Nothing said about "special" cases - FWICT they were exploding combinatorially for the general case.

I was referring to the slides Darwen presented at Warwick Uni some time ago - "Missing info without nulls" which I perhaps erroneously associated with their TTM.

I particularly like the foot note on page 9 ... <quote>
Nothing wrong with the predicates now! And we have reduced the salary part of the database to the simplest possible terms. Yes, some of the complicated queries get more difficult now, because we might have to combine these tables back together again, but the simple queries, such as “How much salary does each person (who has a known salary) earn?” and “Who earns no salary?” become trivial.
</quote>

To me this triplet of sentences is tantamount to blowing your (sic) proverbial foot off with a 155mm field gun even moreso than simply selecting a 12 guage shotty for the job.

But then I could be wrong!

Cheers, Frank. Received on Tue Apr 25 2006 - 11:45:45 CEST