PL/SQL UTL_FILE.FCLOSE

The UTL_FILE.FCLOSE procedure is part of Oracle’s UTL_FILE package, which is used for interacting with operating system files from within PL/SQL. Specifically, the UTL_FILE.FCLOSE procedure is used to close a file that was previously opened using UTL_FILE.FOPEN or UTL_FILE.FOPEN_NCHAR.

Purpose

The UTL_FILE.FCLOSE procedure ensures that the file handle is released and that all buffered data is written to the file before closing it. It is essential to close files properly to avoid file corruption, memory leaks, or other unexpected issues.

Syntax

UTL_FILE.FCLOSE(file_handle IN OUT UTL_FILE.FILE_TYPE);

Parameters

file_handle: This is the file handle returned by UTL_FILE.FOPEN. It represents the file you are working with and is required to close it.

Example

Here is a simple example demonstrating how to open, write to, and then close a file using PL/SQL:

DECLARE
  file_handle UTL_FILE.FILE_TYPE;
  file_dir    VARCHAR2(30) := 'MY_DIR'; -- Directory alias created in Oracle DB
  file_name   VARCHAR2(30) := 'test_file.txt';
BEGIN
  -- Open a file for writing
  file_handle := UTL_FILE.FOPEN(file_dir, file_name, 'W');
  
  -- Write to the file
  UTL_FILE.PUT_LINE(file_handle, 'Hello, World!');
  
  -- Close the file
  UTL_FILE.FCLOSE(file_handle);
  
  DBMS_OUTPUT.PUT_LINE('File written and closed successfully.');
EXCEPTION
  WHEN OTHERS THEN
    IF UTL_FILE.IS_OPEN(file_handle) THEN
      -- Ensure the file is closed even if an exception occurs
      UTL_FILE.FCLOSE(file_handle);
    END IF;
    RAISE;
END;
/

Key Points

File Handle Management: Always ensure that the file is closed after you are done working with it to prevent issues like data loss or locking of the file.

Error Handling: It’s a good practice to wrap your file operations in exception handling. If an error occurs and the file remains open, you can still close it in the exception handler using UTL_FILE.FCLOSE.

Checking File Status: The UTL_FILE.IS_OPEN function can be used to check whether the file is still open before attempting to close it.

Automatic Close on Program Termination: If the file remains open when the PL/SQL block terminates, Oracle will attempt to close the file automatically. However, this is not a recommended approach because explicit closure of files allows for better control and debugging of the code.

Conclusion

The UTL_FILE.FCLOSE procedure is critical for properly managing file resources in Oracle PL/SQL. By ensuring that files are closed after operations, you maintain both file integrity and efficient resource usage in your PL/SQL programs.