Re: PG rules! (RULES being the word ;->)

That's pretty cool.  I may look into those.  I just like being able to
define that the data stay in a self-consistent format.  Other
programming languages would do well to follow this method.  I'm
programming my front-end in PHP.  I should be able to say

INT i CHECK (i > 0);

when I declare it in PHP, for instance, but this isn't possible; they
don't even have strong typing!

Anyway, I was just writing a table which holds credit card payment
data.  I put in a constraint:

       cardnumber VARCHAR(20) CHECK (luhn10(cardnumber)),

right in the table, so no matter how screwed up anything is, only
valid card numbers can go in the table.  I put foreign key constraints
in so that none of the domain names can ever be without an owner (it's
a domain registry project).  This is how programming should be.

Compare this to PHP or perl, where all variables are strings, or C
where there are memory leaks all over the place unless the programmer
is very skilled and careful.