As an FYI (both to myself and others), Oracle's SQL:2003 OLAP support
(SQL:2003 features T611 and T612), which I first learned about in this
old thread, is very, very handy. Here are a few links to various list
archives where I've talked about it more since, given various addition
links, etc.:
MonetDB on
2006-01-25 (with lots of links).
SQLite on
2005-05-23
(with a trivial dense_rank example),
2005-10-13
(EMA, no recursive queries), and again on
2005-10-13.
Although I know little about it, I suspect the vector-oriented
kdb
database has similar order-aware functionality, although derived from
the APL world, rather than from SQL extensions hacked onto the
fundamentally un-ordered relational model.
Wippler's Vlerq
may be going in a similar direction, although from yet another
background.
I've heard that there is some academic work out there on database
models which natively understand order, and form more powerful
supersets of Codd's relational model. I would have called that a
"vector relation model" or an "ordered relation model", but bizarrely,
apparently what it's actually called is a "set model"! I have not
read it, but
The Set Model for Database and Information Systems
by Mikhail M. Gilula
was recommended to me on that subject.