From: Tom Lane <tgl@sss.pgh.pa.us>
To: Joshua Drake <jd@commandprompt.com>
Cc: kevin kempter <kevin@kevinkempterllc.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: Select all table column names for a specified tablename (per the system catalogs)
Date: Mon, 22 Sep 2008 23:37:10 -0400
Message-ID: <16826.1222141030@sss.pgh.pa.us> (raw)
In-Reply-To: <20080922152950.294284b4@jd-laptop>
References: <E9AEE096-D4FD-4A3E-9FD5-FF134747B040@kevinkempterllc.com>
<20080922152950.294284b4@jd-laptop>
Joshua Drake <jd@commandprompt.com> writes:
> kevin kempter <kevin@kevinkempterllc.com> wrote:
>> ... I got this far (see
>> below) however this query produces additional rows with attname's
>> like tableoid, cmax, xmax ctid, etc.
>>
>> select attname from pg_attribute where attrelid = (select oid from
>> pg_class where relname = 'my_tablename');
> SELECT column_name FROM information_schema.columns WHERE table_name =
> 'table';
If you don't want to use information_schema (which you might well not
want to, because it's a bit slow), the bits you're missing are that you
want to exclude columns with attnum <= 0 (system columns) as well as
those with attisdropped (dropped columns). I don't care for the
subselect part of this either, mainly because it is not schema-aware.
Consider
select attname from pg_attribute
where attrelid = 'my_tablename'::regclass
and attnum > 0 and not attisdropped;
which generalizes to
select attname from pg_attribute
where attrelid = 'my_schema.my_tablename'::regclass
and attnum > 0 and not attisdropped;
whereas your original will not handle that easily.
regards, tom lane
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-admin@postgresql.org
Cc: tgl@sss.pgh.pa.us, jd@commandprompt.com, kevin@kevinkempterllc.com
Subject: Re: Select all table column names for a specified tablename (per the system catalogs)
In-Reply-To: <16826.1222141030@sss.pgh.pa.us>
* 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