Jonah said:
Is it possible to autonumber using blocks of numbers i.e. 0 to 199 for one
table then 100 to 199 for another table?
No, nor should you need to.
Autonumbers exist for one purpose only: to provide a (practically
guaranteed) unique value that can be used as a primary key. The actual value
of the Autonumber field shouldn't matter to anyone: in fact, it's usual not
to let the user see the value.
Not only that, but there's no correlation between an Autonumber field in one
table and an Autonumber field in another table.
