"onedaywhen" wrote in
oups.com:

If you've understood the above you should come to the conclusion
that a sole autonumber column will never make a good PRIMARY KEY
in Access/Jet, because a random/incrementing integer/GUID does not
make a good clustered index. I'd suggest that anyone who uses
their autonumber column in a BETWEEN or GROUP BY construct has got
something wrong in design and/or queries. I'd further suggest that
anyone who uses BETWEEN or GROUP BY constructs which do not
include columns that comprise their PKs are likely to have made a
poor choice of PK.

A random PK would result in the placement of records on as many data
pages as possible, thus improving concurrency.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/