On Wed, 16 Mar 2005 09:52:55 +0100, Martijn Tonies <m.tonies@...> wrote:

>
> > > Then again, who needs wide indices if expression indices are supported.
> :-)
> >
> > What are ``expression indices''?
>
> Indices based on an expression that returns a value instead of being
> based on column values.
>
> I haven't tried it, but imagine something like:
>
> create index index_name on table mytable
> ( upper(mycolumn) )
>
> or
>
> create index index_name on table mytable
> ( substring(mycolumn, 1, 100) )
>
> So you could, for example, index the first 100 characters of a longish
> column instead of the full column value.

Ah, thanks for you description.
This sounds interesting. But how do you actually use those indices?
I mean, they might/will have different content than the original value,
so I guess they'll not automatically be used by the optimizer, will they?
Is there some more detailed information available?

Bye,
Daniel

--
eat(this); // delicious suicide