You know, I think you and I are largely in agreement on what many of the core ideas are yet we differ about what we think valid behavior should be, though we'll quibble in the margins.

A table with bad data in it is an improperly-designed table. A properly designed table cannot, by virtue of it being properly designed, have bad data.

I'll agree to stand corrected if and only if I can also require that there is a unique constraint across all columns. (Simply think that providing a primary key may satisfy that constraint but they miss that it may violate 3NF -- see my response to Celada for more discussion).

As for your comments about "relations", I can only refer you to Date's work. It would take me a loooong time to write out exactly what I am referring to when I say "relation". This term goes back to Codd's initial formulation of the relational model and is loosely analogous to what we refer to as a table.

For the moment, ignoring implementation in favor of behavior, if I'm asking for those cities, what's the logical reason for preferring a bag instead of a set? Can you show how this will consistently lead to more correct results?

(I've a sneaky feeling that neither of us is going to give much ground here :)

Cheers,
Ovid

New address of my CGI Course.

In reply to Re^4: (OT) Why SQL Sucks (with a little Perl to fix it) by Ovid
in thread (OT) Why SQL Sucks (with a little Perl to fix it) by Ovid

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