> The disadvantage of this scheme is that if you repeatedly insert entries
> in the "same place" in the sort order, you halve the available range
> each time, so you'd run out of room after order-of-fifty halvings.
This is not a real issue. If anyone is using an ENUM with 1000 values
in it, they're doing it wrong. However, we'd have to present an
intelligible error message in that case.
The float method would also have a couple other issues:
(1) larger value for the enum order, so more RAM. Do we care?
(2) would need to create a view which hid the floats from admins who
just want to look at the enum ordering.
-- -- Josh Berkus PostgreSQL Experts Inc.
http://www.pgexperts.com