--系统管理员向PG_DIRECTORY系统表中加入目录/temp/：
CREATE OR REPLACE DIRECTORY dir AS '/tmp/';
--打开一个文件并向文件中写入数据                                                                                                                   
DECLARE
  f utl_file.file_type;
  dir text := 'dir';
BEGIN
  f := utl_file.fopen(dir, 'sample.txt', 'w');
  PERFORM utl_file.put_line(f, 'ABC');
  PERFORM utl_file.put_line(f, '123'::numeric);
  PERFORM utl_file.put_line(f, '-----');
  PERFORM utl_file.new_line(f);
  PERFORM utl_file.put_line(f, '*******');
  PERFORM utl_file.new_line(f, 0);
  PERFORM utl_file.put_line(f, '++++++++');
  PERFORM utl_file.new_line(f, 2);
  PERFORM utl_file.put_line(f, '#######');
  PERFORM utl_file.put(f, 'A');
  PERFORM utl_file.put(f, 'B');
  PERFORM utl_file.new_line(f);
  PERFORM utl_file.putf(f, '[1 -> %s, 2 -> %s, 3 -> %s, 4 -> %s, 5 -> %s]', 'gaussdb', 'utl', 'file', 'get', 'line');
  PERFORM utl_file.new_line(f);
  PERFORM utl_file.put_line(f, '1234567890');
  f := utl_file.fclose(f);
END;
/
--在上面写入的文件中读取数据。
DECLARE
  f utl_file.file_type;
  dir text := 'dir';
BEGIN
  f := utl_file.fopen(dir, 'sample.txt', 'r');
  FOR i IN 1..11 LOOP
       RAISE INFO '[%] : %', i, utl_file.get_line(f);
  END LOOP;
END;
/
-- 对文件句柄执行位置偏移，并获取文件的当前位置。                                                                                                 
DECLARE
      l_file   utl_file.file_type;
      l_buffer VARCHAR2(32767);
      dir text := 'dir';
      abs_offset number := 100;
      rel_offset number := NULL;
BEGIN
      l_file := utl_file.fopen(location  => dir,  filename  => 'sample.txt',open_mode => 'R');
      dbms_output.put_line('before fseek: current position is ' || utl_file.fgetpos(file => l_file)); -- before fseek: current position is 0
      utl_file.fseek(file => l_file, absolute_offset=>abs_offset, relative_offset=>rel_offset);
      dbms_output.put_line('fseek: current position is ' || utl_file.fgetpos(file => l_file)); -- fseek: current position is 100
      utl_file.fclose(file=>l_file);
END;
/