Alvaro Herrera <alvherre@commandprompt.com> writes:
> Also, if upgrading is necessary, there will need to be one "upgrade"
> control file that says how to upgrade from version N to N+1.
> I don't think we should really support the downgrade case. It has the
> potential to get too messy -- and for what gain?
I think we could leave that to the extension author to decide. Basically,
what is needed is a script file that says how to replace version M by
version N. If the author cares to supply a script for going from
M to M-1, it's no extra logic in the extension manager to be able to
apply that one. In many cases it wouldn't be very practical to do,
but then you just don't offer the script.
regards, tom lane