> Thanks for your answer Thomas. I think in the case I had in mind I
> would do better with a generator.
>
> Anyways, is it possible to have both, an ascending and a descending
> index on the same column?

Yes. AFAIK the only thing to keep in mind is, that you shouldn't
use for both an UNIQUE index if you want to have unique values,
otherwise the optimizer can be confused in some circumstances.

But I'm not sure.

> Will disk storage for these indexes
> duplicate?

You probably get a more reliable answer with deeper insights from
other persons ;-).


Thomas