Re: SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS

On 20/09/2010 1:40 AM, Brian wrote:
...
> Please go back to school and take an introductory course in logic.
>
> Tuples are supposed to represent propositions. Propositions refer to
> objects in the universe of discourse. In the context of database
> updates, it is a gross oversimplification to assume that the universe
> is nothing but a collection of arbitrary objects that are independent
> of time....

Actually, much, if not all, of db and computing in general depends on gross oversimplification, no matter that some theorists might prefer the more expensive word, abstraction. But there's nothing gross about it if the resulting application is deemed useful.

In the context of this particular application it's an out-of-context non-sequitur to mix up 'the universe' with 'universe of discourse', what I would call an act of high mysticism. Granted that some buyers of systems can be briefly impressed by repetitious bald assertions about propositions and objects and sellers often try to sell more than what's needed but what's important is that formal logic's leverage is that it ignores the real universe. Beyond that it's pointless to pretend there's any deep philosophy germane to the typical db application.

All the original post shows is that it is possible to paint oneself into a corner with rigid preconceptions. The supervisor doesn't need to muddle two different situations/relation values in one database transaction. He could just as easily amend the 'first' work order in one transaction and amend the 'second' one in another transaction, or he could be provided with an interface to do that. Nothing in the given schema relates or 'pairs' the two work order numbers. There might well be an application requirement that needs to be stated, for the supervisor to make such corrections. In fact, given the stated requirements such as they are, there would be nothing illogical in the supervisor amending the 'second' one first and the 'first' one second or a different supervisor amending one or the other. Received on Mon Sep 20 2010 - 18:42:09 CEST