declare
        v_parent_sk      varbit default null;
        v_max_value      integer;
begin
        if new.parent_id is null then 
            select max(tree_leaf_key_to_int(tree_sortkey)) into v_max_value 
              from cr_keywords 
             where parent_id is null;
        else 
            select max(tree_leaf_key_to_int(tree_sortkey)) into v_max_value 
              from cr_keywords 
             where parent_id = new.parent_id;

            select tree_sortkey into v_parent_sk 
              from cr_keywords 
             where keyword_id = new.parent_id;
        end if;

        new.tree_sortkey := tree_next_key(v_parent_sk, v_max_value);

        return new;

end;