make_uid.sql

-- original https://stackoverflow.com/a/19532132/2428230
CREATE FUNCTION make_uid() RETURNS text AS $$
DECLARE
    new_uid text;
    done bool;
BEGIN
    done := false;
    WHILE NOT done LOOP
        new_uid := upper(substring(md5(''||now()::text||random()::text),1,8));
        done := NOT exists(SELECT 1 FROM report_users WHERE confirm_key=new_uid);
    END LOOP;
    RETURN new_uid;
END;
$$ LANGUAGE PLPGSQL VOLATILE;