Re: Little design mistakes that can be easily avoided (2): Listenning to CELKO (and CELKO alikes)

Cimode wrote:
> ...
> What do you think about the design mistakes identified based on this
> thread(that was the real purpose of the thread and the reason for
> commenting CELKO's *taxonomy*)...I am talking about...
>
> --> 1 Defining keys according to human perception
> --> 2 Considering there are several realities (external/internal -
> based on human perception)
> --> 3 Believing in magic
> --> 4 Believing that a key is physical concept
> --> 5 Defining keys in function of lazy people.
> --> 6 Making sense out of CELKO writing and *taxonomies*

Regarding the list above, I only think that it is the rare database that can tolerate multiple perceptions or multiple realities. Lots of db's are subjected to those, but I would say they usually don't tolerate them very well. To be a practical db, I think it's implicit its context is one common agreed understanding or interpretation among its users.

Taxonomies are useful for organizing discussion but dangerous when followed naively. Celko is probably abusing them in order to sell to simpletons or wishful thinkers or the habitually lazy, which seems to be either his chosen market or one that he can't avoid and vice versa.

I don't think there is such a thing as a physical key. Usually I think people are talking about indexes when they use that phrase. As much as anything it's the fault of old-timers (my generation) whose understanding of Codd's ideas was crude at best or more often completely ignorant. Its value is as much in forming a whole fact from a fraction of its parts as it is for enforcing some common perception - in this sense, using a term like superkey in the same context as the term "key" seems pointless (except in a context that is limited, eg., exploring FDs).

Lots of times, a generated ID is useful when nothing better is needed or when nothing better can be found. Some historical writers are certain that there was a Soviet agent number nineteen in the WWII American White House. That is the best ID for him or her that anybody has come up with so far.

p Received on Sun May 27 2007 - 17:57:07 CEST