Reading the data from BLOB column

Question

HI,
I have a table with following structure
Test_Mail(Attachment BLOB,Attachmentname varchar2(255),FileSize number)
The data in the table is like
Attachment|Attachmentname|FileSize
BLOB|test.txt|1236
I wants to read the data from the BLOB attachment in to new file.
can any one help me in doing this with plsql??
Thanks in advance,
Balaji tk.
Edited by: Balaji.tk on Jan 9, 2011 9:28 PM

Answer 1

May be something like this ?
DECLARE
   l_file       UTL_FILE.FILE_TYPE;
   l_buffer     RAW (32767);
   l_amount     BINARY_INTEGER     := 32767;
   l_pos        INTEGER            := 1;
   l_blob       BLOB;
   l_blob_len   INTEGER;
BEGIN
-- Open the destination file.
   l_file := UTL_FILE.FOPEN ('TEST_DIR', v_attachment_name, 'wb');
   --This v_attachment_name can be selected from your table.
-- Get LOB locator
FOR rec IN (
SELECT attachment   l_blob
      FROM test_mail
     --Your where condition to find the row.      
   --AND ROWNUM =1
LOOP
   l_blob_len := DBMS_LOB.getlength (rec.l_blob);
-- Read chunks of the BLOB and write them to the file
-- until complete.
   WHILE l_pos < l_blob_len
   LOOP
      DBMS_LOB.READ (rec.l_blob, l_amount, l_pos, l_buffer);
      UTL_FILE.put_raw (l_file, l_buffer, FALSE);
      l_pos := l_pos + l_amount;
   END LOOP;
  commit;
END LOOP;
-- Close the file.
   UTL_FILE.FCLOSE (l_file);
EXCEPTION
   WHEN OTHERS
   THEN
-- Close the file if something goes wrong.
      IF UTL_FILE.IS_OPEN (l_file)
      THEN
         UTL_FILE.FCLOSE (l_file);
      END IF;
      RAISE;
END;