Re: trigger functions with arguments

Kev wrote:
> I came across this curious behaviour today, at least in the 2009-03-24
> beta (I can't run a newer beta), that I couldn't find in the docs,
> although maybe I missed it.

[...]

> So while that is the way to create the trigger itself, the
> trigger procedure must be created like this:
>
> CREATE OR REPLACE FUNCTION test() RETURNS trigger AS $BODY$
> my ($a, $b) = @{$_TD->{args}}; # $a and/or $b may be null, depending on how CREATE TRIGGER was used
> ...

Maybe it is hidden too well, but the documentation states in
http://www.postgresql.org/docs/current/static/plpgsql-trigger.html

A trigger procedure is created with the CREATE FUNCTION command, declaring it
as a function with no arguments and a return type of trigger. Note that the function
must be declared with no arguments even if it expects to receive arguments
specified in CREATE TRIGGER - trigger arguments are passed via TG_ARGV,
as described below.

Yours,
Laurenz Albe