CREATE GLOBAL TEMPORARY TABLE obj_list (
    id_list    int NOT NULL,
    id_obj    int NOT NULL,
    n  varchar(200)
) ON COMMIT DELETE ROWS;
ALTER TABLE obj_list ADD CONSTRAINT pk_obj_list PRIMARY KEY (id_list, id_obj);

execute block
returns (
    name type of column rdb$relation_fields.rdb$field_name)
as
    declare variable id_list int;
    declare variable n type of column rdb$relation_fields.rdb$relation_name;
    declare cur cursor for (
        select
            l.n
        from obj_list l
        where
            l.id_list = :id_list
    );
begin
    id_list = 1;
    n = 'RDB$FIELDS';
    merge into obj_list d
    using (
        select
            row_number() over() as id,
            rf.rdb$field_name as n
        from rdb$RELATION_FIELDS rf
        where
            rf.rdb$relation_name = :n
    ) s
    on d.id_list = :id_list and d.id_obj = s.id
    when not matched then
        insert (id_list, id_obj, n)
        values (:id_list, s.id, s.n);

    --suspend;
    open cur;
    while (true) do begin
        fetch cur into :name;
        if (row_count = 0) then
            break;
        suspend;
    end
    close cur;
end