Re: A good book

Bob Badour <bbadour_at_pei.sympatico.ca> wrote:
> Chris Smith wrote:
> > I'm suggesting that you've yet to establish the connection between:
> >
> > (a) predicate calculus and elegant code
> > (b) databases and predicate calculus
>
> Relational calculus = 1st order predicate calculus
>
> Am I missing something?

No, you're almost certainly not missing something. Nevertheless, what I'm asking for ought to be relatively simple, so I'll try to explain it another way.

As is pointed out here several times every five minutes (okay, not that often...), database design and programming is rather frequently and unfortnuately performed from very little theoretical basis at all. At the same time, it's frequently stated that relational databases operate on a solid mathematical foundation. That's a useful statement if and only if that mathematical foundation provides tools that are useful in practice for reasoning about behavior, transformations, correctness, etc. of the code written in relational languages. If this connection is not made, then all this talk about predicate calculus is pointless. I am looking for the sources that explain how this connection is made. Are there theorems of relational theory that suggest certain program transformations, or certain criteria for correctness? You made a comment in another thread that suggested that features added to relational databases can be traced back to the mathematical model; where's a source that explains how? Although it's not a specialty of mine, I have a pretty solid layman's knowledge of systems of logic, including predicate calculus, but it's entirely non-obvious to me how this would effect my use of or implementation of a database system. This is what I'm asking for. Or at least, that's the theoretical part of what I'm asking for, which I called (b). The practical part is (a), but I imagine it will largely follow from the theoretical understanding.

> Life is too short to go digging for it, but one EWD stands out in regard
> to elegance where EWD provided a proof without iteration for something
> previously proved using iteration. He used it as an example of greater
> elegance.

Hopefully, I've explained why this isn't what I want.

-- 
Chris Smith - Lead Software Developer / Technical Trainer
MindIQ Corporation