create function and trigger to update column on table update - Mailing list pgsql-novice

From Dara Olson
Subject create function and trigger to update column on table update
Date
Msg-id 5B6943440B4A4F16A1A77D0EA21E07B5@GISWKSTN2
Whole thread Raw
Responses Re: create function and trigger to update column on table update
Re: create function and trigger to update column on table update
List pgsql-novice
I am new to creating triggers/functions.  I am trying to create a trigger and function that when a specific table is updated or records added that it updates an existing column (catalog_number) from an existing column and latitude/longitude.  Below is what I have so far.  Does anyone know what I am doing wrong or if I am going in the complete wrong direction?  Is there a way to define that the column only gets updated on the records that were updated or inserted. Any help would be greatly appreciated!
Thanks!
Dara
 
CREATE OR REPLACE FUNCTION invasive_species.update_catalog_number() RETURNS TRIGGER AS
'BEGIN
 
IF TG_OP = "UPDATE" THEN
UPDATE invasive_species.invspp_occurrence_data
SET catalog_number = "tsn_char" || $_$ || x(centroid(transform(the_geom, 4326)))|| $_$ || y(centroid(transform(the_geom, 4326)));
 
RETURN NEW;
END IF;
RETURN NULL;
END;'
LANGUAGE plpgsql;
 
CREATE TRIGGER catalog_num_trigger AFTER UPDATE ON invasive_species.invspp_occurrence_data
FOR EACH ROW EXECUTE PROCEDURE update_catalog_number();

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