"Fred" wrote in message
...
One other advantage of autonumber keys that is probably too obvious to
mention is that it takes no work, skill or carefulness for the person to
enter and enter it properly.

One other advantage is that this that this number (relied upon for DB
operation) can't be "messed with" by others. For example, if you use a
part
number or a membership ID number as a PK, and then some department that
controls part numbers or membership ID numbers says "oh, we
changed/corrected
that number" they are just changing a piece of data rather than a PK.

FWIW my take on this is similar (if not the same) as Allen's - I use a
natural key for a look-up table and an AutoNumber for just about everything
else.

2p supplied

Keith.
www.keithwilby.co.uk