From: Kevin Grittner <kgrittn@ymail.com>
To: Campbell, Lance <lance@illinois.edu>
To: pgsql-admin@postgresql.org <pgsql-admin@postgresql.org>
Subject: Re: update Timestamp updated whenever the table is updated
Date: Tue, 12 Feb 2013 14:00:42 -0800 (PST)
Message-ID: <1360706442.33888.YahooMailNeo@web162906.mail.bf1.yahoo.com> (raw)
In-Reply-To: <B75CD08C73BD3543B97E4EF3964B7D701F15773D@CITESMBX1.ad.uillinois.edu>
References: <B75CD08C73BD3543B97E4EF3964B7D701F15773D@CITESMBX1.ad.uillinois.edu>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-admin>
"Campbell, Lance" <lance@illinois.edu> wrote:
> I would like to have a generic strategy for updating a timestamp
> field on some tables whenever the table is updated. Is there a
> recommended strategy for doing this other than via the SQL UPDATE
> command?
> Example table:
> CREATE TABLE test_table
> (
> id integer NOT NULL,
> field1 character varying NOT NULL,
> field2 character varying NOT NULL,
> updated_timestamp timestamp with time zone DEFAULT now(),
> created_timestamp timestamp with time zone DEFAULT now()
> );
A BEFORE UPDATE trigger is probably what you want. You could write
a single trigger function which could be attached to all tables
with the updated_timestamp column. For example:
CREATE FUNCTION set_updated_timestamp()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
NEW.updated_timestamp := now();
RETURN NEW;
END;
$$;
Note that the above function depends on a column name, but not a
table name. You link it to each table like this:
CREATE TRIGGER test_table_update_timestamp
BEFORE UPDATE ON test_table
FOR EACH ROW EXECUTE PROCEDURE set_updated_timestamp();
> I think I read something about RULES.
You generally want to avoid RULES, especially where a trigger works
so well.
--
Kevin Grittner
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin
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: kgrittn@ymail.com, lance@illinois.edu
Subject: Re: update Timestamp updated whenever the table is updated
In-Reply-To: <1360706442.33888.YahooMailNeo@web162906.mail.bf1.yahoo.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