hstore trigger

create extension if not exists hstore

drop table public.product;

create table public.product (
	id serial,
	nr int not null,
	name varchar(100) not null,
	names hstore null,
	growing_months int[] null constraint valid_month check (growing_months <@ ARRAY[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]),
	season daterange null
)

create or replace function default_language()
returns trigger as
$BODY$
begin
	NEW.names = COALESCE(NEW.names, '') || hstore('en', NEW.name);
	return NEW;
end;
$BODY$
language plpgsql;

create trigger i_product_name before insert on public.product for each row execute procedure default_language();
create trigger u_product_name before update on public.product for each row when (OLD.name IS DISTINCT FROM NEW.name) execute procedure default_language();

insert into public.product (nr, name, names, growing_months, season) values (847, 'Bicycle', ('nl => Fiets')::hstore, ARRAY[1, 2, 11, 12], '[2014-01-04, 2014-05-06]')
select * from product
update product set name = 'Bycicle' where id = 1;