On Sat, Dec 20, 2003 at 04:14:51PM -0800, Jeff Davis wrote:
> > >
> > > What, exactly, is a partial index? A functional index is an index on
> > > something like ((ColumnX*2)/14)? I think the functional one (is that
> > > also an expression index?) is on the way.
> >
> > A partial index is a index on a subset of a table. The case I can think of
> > is a list of transactions, some of which are yet to be billed. They have a
> > BillID field which is NULL. since this is the recent set it is queried quite
> > often, so you can build an index like:
> >
>
> Are NULLs even indexed?
No, but with a partial index you can acheive the same effect.
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> (... have gone from d-i being barely usable even by its developers
> anywhere, to being about 20% done. Sweet. And the last 80% usually takes
> 20% of the time, too, right?) -- Anthony Towns, debian-devel-announce