Re: Performance question

From: Howard J. Rogers <dba_at_hjrdba.com>
Date: Wed, 29 May 2002 09:38:38 +1000
Message-ID: <ad14go$gkk$1@lust.ihug.co.nz>

The format of a row is: row header, column length - value; column length - value; column length - value; and so ad infinitum (nearly).

The length of a field is stored as an attribute within the row. If it was Name Char(10) it would be stored as :10:Smith-----: If it was Name varchar2(10) it would be stored as :5:Smith:

Regards
HJR "Eric Levinson" <nospam_at_nospam.com> wrote in message news:DjUI8.4416$3w2.19388_at_typhoon.sonic.net...
> When a VARCHAR2 type column is defined, how does the LENGTH function get
the
> length of the varchar contained in the column? Does it count up the
number
> of bytes to some end of string marker, or is there an internally held and
> maintained attribute of varchar which maintains the size?
>
> Reason why I am asking, there might be a performance hit to use LENGTH if
it
> has to calculate it every time.
>
> Any help would be appreciated
>
> oracle at levinsong dot com
>
>
Received on Tue May 28 2002 - 18:38:38 CDT