create temp table test_data (
    id int not null,
    data text not null
);

with short as (select array_agg(iso) c from countries),
series as (select i from generate_series(1, 500) as i)
insert into test_data (id, data) 
    select series.i, substr(md5(random()::text), 0, floor(random() * 25 + 2)::int) || '.' || (short.c)[floor(random() * 239+1)] from series, short;