Re: Partitioning documentation example

bruce wrote:
> Simon, I was looking at the new table partitioning documentation that
> recommends triggers:
>
> http://developer.postgresql.org/pgdocs/postgres/ddl-partitioning.html#DDL-PARTITIONING-IMPLEMENTATION
>
> and came upon this trigger function example:
>
> CREATE OR REPLACE FUNCTION measurement_insert_trigger()
> RETURNS TRIGGER AS $$
> BEGIN
> IF ( NEW.logdate >= DATE '2006-02-01' AND NEW.logdate < DATE '2006-03-01' ) THEN
> INSERT INTO measurement_y2006m02 VALUES (NEW.*);
> ELSIF ( NEW.logdate >= DATE '2006-03-01' AND NEW.logdate < DATE '2006-04-01' ) THEN
> INSERT INTO measurement_y2006m03 VALUES (NEW.*);
> ...
> ELSIF ( NEW.logdate >= DATE '2008-01-01' AND NEW.logdate < DATE '2008-02-01' ) THEN
> INSERT INTO measurement_y2008m01 VALUES (NEW.*);
> ELSE
> RAISE EXCEPTION 'Date out of range. Fix the measurement_insert_trigger() function!';
> END IF;
> RETURN NULL;
> END;
> $$
> LANGUAGE plpgsql;

Because my EXECUTE example didn't work I have created a new example
using date_trunc(), which I think is less error-prone than the
comparisons done in the original example:

CREATE OR REPLACE FUNCTION measurement_insert_trigger()
RETURNS TRIGGER AS $$
BEGIN
IF date_trunc('month', NEW.logdate) = '2006-02-01' THEN
INSERT INTO measurement_y2006m02 VALUES (NEW.*);
ELSIF date_trunc('month', NEW.logdate) = '2006-03-01' THEN
INSERT INTO measurement_y2006m03 VALUES (NEW.*);
...
ELSIF date_trunc('month', NEW.logdate) = '2008-01-01' THEN
INSERT INTO measurement_y2008m01 VALUES (NEW.*);
ELSE
RAISE EXCEPTION 'Date out of range. Fix the measurement_insert_trigger() function!';
END IF;
RETURN NULL;
END;
$$
LANGUAGE plpgsql;

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

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