"Brendan Jurd" <direvus@gmail.com> writes:
> Has anyone had a close look at how hard it would be allow just the
> "add to the end" capability?
The problem is you can't guarantee anything about the ordering of the
new value relative to the old ones. The OID it's assigned might be
after them, or before them if the OID counter has wrapped around,
or (with much smaller probability) between two existing ones.
This is something we consciously gave up when we selected the current
ENUM implementation.
regards, tom lane