[postgis-users] Trigger question

[Stephen Davies]

G'day all.
This is probably an FAQ but I don't see it.

I am trying to write a plpgsql trigger to calculate and store the area 
of a polygon but am getting no result.

The latest version of my code is:

create function setarea() returns trigger as $setarea$
declare
 a numeric (10,2);
begin
 select into a area(transform(NEW.geom,28354));
 NEW.area := a;
 return NEW;
end;
$setarea$ language plpgsql;
create trigger setarea after insert or update on unit for each row 
execute procedure setarea();

This generates no error at creation or update time but does not give me 
an area either.

What amI missing?

Cheers and thanks,
Stephen Davies
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