Re: Oracle 11g Virtual Columns?
From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Wed, 21 Jan 2009 10:12:21 +0000 (UTC)
Message-ID: <gl6se5$lvi$1_at_solani.org>
On Tue, 20 Jan 2009 21:33:05 +0000, Jonathan Lewis wrote:
Date: Wed, 21 Jan 2009 10:12:21 +0000 (UTC)
Message-ID: <gl6se5$lvi$1_at_solani.org>
On Tue, 20 Jan 2009 21:33:05 +0000, Jonathan Lewis wrote:
> If you create a function based index on (sal + nvl(comm,0)) then you
> have a hidden column definition, but can generate real statistics on the
> values - but you have to have the index when (possibly) all you really
> want is the stats.
And, on 11G you can generate an extended stats, so that you can reap the benefits even without the virtual column. Of course, generating an extended stats does create a virtual hidden column for you....
-- Mladen Gogala http://mgogala.freehostia.comReceived on Wed Jan 21 2009 - 04:12:21 CST