CREATE OR REPLACE FUNCTION get_schema_version() RETURNS int
    LANGUAGE sql
    AS $$
    SELECT max(version) FROM public.gemma_schema_version;
$$;

CREATE OR REPLACE FUNCTION is_country(code char) RETURNS boolean
AS $$
    SELECT EXISTS(SELECT 1 FROM public.countries WHERE country_code = code)
$$
    LANGUAGE sql
    STABLE PARALLEL SAFE;