declare
        v_parent_sk     varbit default null;
        v_max_value     integer;
        ctx_id          integer;
        v_rec           record;
        clr_keys_p      boolean default 't';
begin
        if new.bookmark_id = old.bookmark_id and 
           ((new.parent_id = old.parent_id) or
            (new.parent_id is null and old.parent_id is null)) then

           return new;

        end if;

        for v_rec in select bookmark_id
                       from bm_bookmarks 
                      where tree_sortkey between new.tree_sortkey and tree_right(new.tree_sortkey)
                   order by tree_sortkey
        LOOP
            if clr_keys_p then
               update bm_bookmarks set tree_sortkey = null
               where tree_sortkey between new.tree_sortkey and tree_right(new.tree_sortkey);
               clr_keys_p := 'f';
            end if;
            
            select parent_id into ctx_id
              from bm_bookmarks 
             where bookmark_id = v_rec.bookmark_id;

            if ctx_id is null then 
                select max(tree_leaf_key_to_int(tree_sortkey)) into v_max_value
                  from bm_bookmarks 
                 where parent_id is null;
            else 
                select max(tree_leaf_key_to_int(tree_sortkey)) into v_max_value
                  from bm_bookmarks 
                 where parent_id = ctx_id;

                select tree_sortkey into v_parent_sk 
                  from bm_bookmarks 
                 where bookmark_id = ctx_id;
            end if;

            update bm_bookmarks 
               set tree_sortkey = tree_next_value(v_parent_sk, v_max_value)
             where bookmark_id = v_rec.bookmark_id;

        end LOOP;

        return new;

end;