How to write a LOB to a file.

Question

Hi,
I have a requirement to download files from a Client PC to our database server, store them in our Oracle database as a LOB, and then later reverse the process by extracting the LOB from Oracle to a file and then transmit the file back to the client PC.
The files are of many different types (pdf, jpeg, wpd, doc, ......).
The stored procedure that our web client invokes to take the file and store it as a LOB is as follows:
PROCEDURE large_objV3(
v_filename IN VARCHAR2,
v_mime_typ_cd IN VARCHAR2 )
IS
bfile_in BFILE := NULL;
large_obj sp_large_obj%ROWTYPE;
BEGIN
Associate the bfile pointer to file that resides in the file system of the host
operating system. This file must be located in the directory pointed to by the
Oracle directory object.
bfile_in := BFILENAME( 'name of a directory object', v_filename );
/* Open the input file */
DBMS_LOB.FILEOPEN(bfile_in);
/* Get the next id number for the new row */
SELECT large_obj_s.nextval
INTO large_obj.large_obj_id
FROM DUAL;
/* Create large object record */
INSERT INTO large_obj(
large_obj_id,
binary_lob)
VALUES(
large_obj.large_obj_id,
EMPTY_BLOB())
RETURNING binary_lob
INTO large_obj.binary_lob;
/* Copy contents of the file to blob */
DBMS_LOB.LOADFROMFILE(
large_obj.binary_lob,
bfile_in,
DBMS_LOB.GETLENGTH(bfile_in),
1,
1);
COMMIT;
/* Close the input file */
DBMS_LOB.CLOSE(bfile_in);
This works fine. The problem is that bfiles are read only and the DBMS_LOB package does not have an reverse operation to LOADFROMFILE to reverse the process.
Does anyone have any suggestions on how to accomplish writing the LOB to a binary file on the host operating system?
Any help much appreciated

Answer 1

You can use java. I wrote a bean that has two procedures that might be useful to you one is File_Utils.fileToLob and one is File_Utils.lobToFile.
The code is free and can be found at
www.ckamco.com/FileUtils.zip