Alan,

AM> isn't it time we picked up on a bit of "slang" and brought it into
AM> legitimacy?

no. You don't have to use null if you don't want to.
Just define everything as not null, abound with default values and use
out-of-band values to signal unknown values.

You can build a perfect relational database without needing to even
know that null exists.

Ciao
--
Nando mailto:nandod@...