求大神解析一下下面几句代码是什么意思

jun277

create or replace FUNCTION F_EXPORT_TO_FILE(read_chunk_size number, write_chunk_size number, dump_query sys_refcursor)
    RETURN return_type PIPELINED
    parallel_enable(partition dump_query by any)
    IS
                    type result_line is record(
                                col1 varchar2(4000),
                                col2 varchar2(4000),
                                );
        TYPE row_type IS TABLE OF result_line;
        dump_records row_type;