Re: Wrong insert before trigger examples

On Wed, Feb 5, 2020 at 09:36:49AM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/12/ddl-partitioning.html
> Description:
>
> Hi,
>
> I just noticed that the example in 5.11.3.1. Point 5 contains an "before
> insert trigger" which will not work anymore (I think since Postgres 12).
> This trigger is not needed anymore and causes an error message.

Sorry for the delay in replying. I was able to successfully create the
trigger:

CREATE TABLE measurement (
city_id int not null,
logdate date not null,
peaktemp int,
unitsales int
);

CREATE TABLE measurement_y2006m02 (
CHECK ( logdate >= DATE '2006-02-01' AND logdate < DATE '2006-03-01' )
) INHERITS (measurement);

CREATE INDEX measurement_y2006m02_logdate ON measurement_y2006m02 (logdate);

CREATE OR REPLACE FUNCTION measurement_insert_trigger()
RETURNS TRIGGER AS $$
BEGIN
INSERT INTO measurement_y2008m01 VALUES (NEW.*);
RETURN NULL;
END;
$$
LANGUAGE plpgsql;

CREATE TRIGGER insert_measurement_trigger
BEFORE INSERT ON measurement
FOR EACH ROW EXECUTE FUNCTION measurement_insert_trigger();

There are actually two definitions of 'measurement' in the docs above,
and you might have used the partitioned one:

CREATE TABLE measurement (
city_id int not null,
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (logdate);

I have developed the attached patch to clarify which definition to use.
I am not sure if more extensive changes are needed.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EnterpriseDB https://enterprisedb.com

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