Oracle DB 檢查檔案是否存在

最近寫的，在 oracle 9i 底下，檢查檔案是否存在

-- 驗證檔案是否存在
FUNCTION chk_exists(p_dir IN VARCHAR2, p_filename IN VARCHAR2)
  RETURN BOOLEAN IS
  /* declare an handle for the file */
  fhandle  utl_file.file_type;
  v_exists BOOLEAN;
BEGIN
  v_exists := FALSE;
  /* try openning file for reading */
  fhandle := utl_file.fopen(p_dir, p_filename, 'R');
 
  IF utl_file.is_open(fhandle) THEN
    v_exists := TRUE;
    utl_file.fclose(fhandle);
  END IF;
 
  RETURN v_exists;
EXCEPTION
  -- in any error case report that file does not exist.
  WHEN OTHERS THEN
    RETURN FALSE;
END chk_exists;
 
-- 複製檔案
FUNCTION exe_fcopy(p_dir1  IN VARCHAR2,
                   p_file1 IN VARCHAR2,
                   p_dir2  IN VARCHAR2,
                   p_file2 IN VARCHAR2) RETURN BOOLEAN IS
BEGIN
  -- 將 p_dir1 的 p_file1 複製到 p_dir2 的 p_file2
  utl_file.fcopy(p_dir1, p_file1, p_dir2, p_file2);
 
  RETURN TRUE;
EXCEPTION
  WHEN OTHERS THEN
    RETURN FALSE;
END exe_fcopy;