Unable to read BLOB column

Question

Hi,
I want to read data in text format from the BLOB column
XML_col is the column with BLOB datatype in TEST table.
select BLOB2VARCHAR(XML_col) from TEST;
I created BLOB2VARCHAR function to convert from BLOB to Varchar.
CREATE OR REPLACE FUNCTION TEST_fnc (html IN BLOB)
RETURN VARCHAR2
IS
tmpvar NUMBER;
tmpchr VARCHAR2 (4000);
BEGIN
tmpchr := UTL_RAW.cast_to_varchar2 (DBMS_LOB.SUBSTR (html, 4000, 1));
tmpchr := SUBSTR (tmpchr, 1, 4000);
RETURN tmpchr;
EXCEPTION
WHEN OTHERS
THEN
RETURN NULL;
END blob2varchar;
I am getting output as ’
Which i guess is wrong.

Answer 1

Hi,
This will print your output character by character
Try this and let me know
DECLARE
   v_read_bytes  BINARY_INTEGER;
   v_pos         INTEGER;
   v_blob_len    INTEGER;
   v_buffer      RAW(200);
   v_file_data   fnd_lobs.file_data%TYPE;
BEGIN
         SELECT file_data
           INTO v_file_data
           FROM fnd_lobs
          WHERE file_id = 121708;
         v_blob_len    := DBMS_LOB.getLength (v_file_data);
         v_pos         := 0;
         v_read_bytes  := 1;
         WHILE v_pos <= v_blob_len
         LOOP
            v_pos         := v_pos +  1;
            DBMS_LOB.read (v_file_data, v_read_bytes, v_pos, v_buffer);
            DBMS_OUTPUT.PUt_line(utl_raw.cast_to_varchar2(v_buffer));
         END LOOP;
END;