PostgreSQL: functions don't hold static references to the objects.

example.sql

create table a (isOk BOOLEAN not null);

CREATE or replace FUNCTION get_isOk ( )
returns BOOLEAN as $$
  select isOk from faa;
$$ LANGUAGE SQL;

drop table a;

-- select get_isOk(); -- now fails

create table a (isOk BOOLEAN not null);

select get_isOk(); -- works!