Re: Wrong insert before trigger examples

Patch applied back through PG 10.

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On Fri, Mar 13, 2020 at 06:56:37PM -0400, Bruce Momjian wrote:
> 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
>
> + As you are, so once was I. As I am, so you will be. +
> + Ancient Roman grave inscription +

> diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
> index 8d3a0d1c22..d2588876c0 100644
> --- a/doc/src/sgml/ddl.sgml
> +++ b/doc/src/sgml/ddl.sgml
> @@ -4103,8 +4103,8 @@ ALTER INDEX measurement_city_id_logdate_key
> <title>Example</title>
>
> <para>
> - We use the same <structname>measurement</structname> table we used
> - above. To implement partitioning using inheritance, use
> + We use the non-partitioned <structname>measurement</structname>
> + table above. To implement partitioning using inheritance, use
> the following steps:
>
> <orderedlist spacing="compact">

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

+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +