Re: interest of indexes ....

From: Chris Leonard <chris_at_databaseguy.com>
Date: 17 Jun 2002 15:43:31 -0700
Message-ID: <b8cc3cda.0206171443.2af246e@posting.google.com>

Fred - Except for covered queries (this means a query where all the required data can be found in indexes without any access to the actual data heap), indexes will not help a query like the one you list: it's like handing somebody a phone book and saying "find everyone whose last name has an 'e' in it." Since your query is not covered, an index will not help.

HTH,
Chris

---

Chris Leonard
MCSE, MCDBA, MCT, OCP, CIW
The Database Guy at PPI
http://www.propoint.com
Brainbench MVP for Oracle Admin
http://www.brainbench.com

Fred Burlaud <fburlaud_at_com6.fr> wrote in message news:<3D0DE076.20404_at_com6.fr>...
> Hello,
>
>
> An index works for search of the complete string of the field but
> is it appropiated for the substring search too
>
> For ex. I would like to know if an index on phone field is appropriated
> in this case
>
> SELECT * From Contact WHERE phone like '%0867%';
>
> Thanks
> Fred
Received on Mon Jun 17 2002 - 17:43:31 CDT