Message-ID: <39B6360A.8FEE705@greatbridge.com>
Date: Wed, 06 Sep 2000 08:18:18 -0400
From: Chris Ryan <chris@greatbridge.com>
Organization: GreatBridge LLC
MIME-Version: 1.0
To: craig.may@s2.enthdimension.com.au
CC: pgsql-sql@postgresql.org
Subject: Re: Trigger
References: <20000906202707.A4767@s2.enthdimension.com.au>
Content-Type: text/plain; charset=us-ascii
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Craig May wrote:
> 
> Could someone send me a quick example of a trigger.

Hope this helps.

Chris Ryan

<<< Clip below and execute to create example >>>
--
-- FUNCTION: trigger_last_updated
--
-- DESCRIPTION:
-- This is a function called by the table triggers to update the
last_updated
-- field on insert and updates.
--
create function trigger_last_updated()
    returns opaque
    as 'begin
            new.last_updated := now();
            return new;
        end;'
    language 'plpgsql';

--
-- TABLE: test_tbl
--
-- DESCRIPTION:
-- A simple table to test my trigger
--
create table test_tbl (
    some_field varchar(10),
    last_updated timestamp not null default now()
);

--
-- TRIGGER: trigger_insert_update_test_tbl
--
-- DESCRIPTION:
-- This is the trigger called on insert and updates of all the table
that
-- has the last_updated field. It will use the function
trigger_last_updated
-- The cool thing here is the function doesn't make specific reference
to the
-- table so you could create a different trigger for each table with the
field
-- last_updated and use the same function.
--
create trigger trigger_insert_update_test_tbl
    before insert or update on test_tbl
    for each row execute procedure trigger_last_updated();