Gary Stainburn <gary.stainburn@ringways.co.uk> writes:
> My question is this. Is there a safe way of retrieving the next
> number from the parameter table in such a way that the same number
> cannot be retrieved twice.
Use a SEQUENCE object for each "parameter table". This gives you
a well-tested, efficient generator mechanism. It may be "auto
generated" but you do have the option of resetting the sequence's
nextval and so forth, so I don't see that there is a good reason
to build a SEQUENCE substitute by hand.
regards, tom lane