Re: Dreaming About Redesigning SQL

Anthony,

> And don't other databases have both theory and model?

Actually, no, the "new" databases do not.

The relational model is backed by relational algebra and relational calculus,
plus a series of postulates and laws which have been refined and tested over
20 years.

Not Object-Oriented databases nor XML "databases", nor Multi-Value databases
have any body of theory behind them, mathematical or otherwise. I defy you
to post a single paper that has a mathematical theory for MV or OODB, or even
a firm set of laws that govern such a database. Nor is the industry moving
toward developing such a theory; instead the marketeers of commercial OODB
and XMLDB use a lot of ink to denigrate the idea of mathematical theory as
antiquated and stuffy, and in one case even using their advertising clout to
drive critical theorists off the pages of IT magazines (see Fabian Pascal's
web page).

Actually, amusingly enough, there is a body of theory backing XML databases,
but it's not one any current devloper would want to admit to: the XML
database is functionally identical to the Network Databases of the 1960's.
Of course, Network Databases gave way, historically, to Relational for good
reason.

And MV databases, despite decades of existence, never developed any theory
behind them at all, possibly because one is not possible; MV databases are
entirely an ad-hoc creation designed to work around decade-old limits in
computer processing. Pick is merely TextMagic revived and put on the web.

Now, OODB could certainly *develop* a model and theory, and I think it's high
time it did. The Zope project has amply demonstrated the usefulness of OODB
for certain applications. But as long as there is no OODB calculus, and no
industry-agreed model, and no ANSI standard language or interface, each and
every OODB will be 100% incompatible with every other one ... severely
limiting their utility.

The importance of theory, model, and standards is *not* to be overstated in an
industry where every year the industry-favorite commerical databases get more
ad-hoc, further from the theory, and more callous in their disregard of
international standards.

FWIW, I share your dissatisfaction with SQL, but because it's not relational
enough rather than the other way around.

--
Josh Berkus
Aglio Database Solutions
San Francisco