From: David Hartwig <daveh@insightdist.com>
To: Bruce Momjian <maillist@candle.pha.pa.us>
Cc: Hannu Krosing <hannu@trust.ee>
Cc: byronn@insightdist.com
Cc: pgsql-hackers@postgreSQL.org
Cc: pgsql-interfaces@postgreSQL.org
Subject: Re: [HACKERS] Re: [INTERFACES] retrieving varchar size
Date: Thu, 23 Apr 1998 15:29:55 -0400
Message-ID: <353F96B3.E75DB188@insightdist.com> (raw)
References: <199804231736.NAA29768@candle.pha.pa.us>
Bruce Momjian wrote:
> >
> > In the latter case, I would suggest an additional SQL command for open
> > cursors,
> > or a pseudo table for open cursor where you could do a simple select
> > statement:
> >
> > DECLARE CURSOR FOO_CURSOR FOR SELECT * FROM MYTABLE;
> >
> > SELECT _FIELD_NAME,_FIELD_TYPE,_FIELD_SIZE FROM
> > FOO_CURSOR_INFO_PSEUTOTABLE;
>
> The information you want is in pg_attribute.atttypmod. It is normally
> -1, but is set for char() and varchar() fields, and includes the 4-byte
> length. See bin/psql/psql.c for a sample of its use.
I see everyone writing in terms of length. You do mean precision, don't
you? For our purposes, this precision should arrive in the result
header. (redundancy in each tuple could be over looked) The goal is to be
able to put realistic bounds on memory allocation before the entire result is
read in. For this to work, functions must also be able to propagate the
their precision.
Did I spell doom to this idea?
Attachments:vcard.vcf (text/x-vcard, 202B) download
begin: vcard
fn: David Hartwig
n: Hartwig;David
email;internet: daveh@insightdist.com
x-mozilla-cpt: ;0
x-mozilla-html: FALSE
version: 2.1
end: vcard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-interfaces@postgresql.org
Cc: daveh@insightdist.com, maillist@candle.pha.pa.us, hannu@trust.ee, byronn@insightdist.com, pgsql-hackers@postgreSQL.org
Subject: Re: [HACKERS] Re: [INTERFACES] retrieving varchar size
In-Reply-To: <353F96B3.E75DB188@insightdist.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox