Problem with DBMS_LOB.SUBSTR

Question

Hi,
i want to encode a BLOB into BASE64_ENCODE.
Here my PL/SQL function:
FUNCTION encodeBlob2Base64(pBlobIn IN BLOB)
RETURN BLOB
IS
vAmount PLS_INTEGER := 20000;
vBase64Blob BLOB;
vBlobIn BLOB;
vOffset PLS_INTEGER := 1;
BEGIN
vBlobIn := pBlobIn;
dbms_lob.createtemporary(lob_loc => vBase64Blob, CACHE => FALSE);
LOOP
dbms_lob.append(dest_lob => vBase64Blob,
src_lob => utl_encode.base64_encode(r =>
dbms_lob.substr(lob_loc => vBlobIn, amount => vAmount, offset => vOffset)));
vOffset := vOffset + vAmount;
END LOOP;
dbms_lob.freetemporary(lob_loc => vBase64Blob);
RETURN vBase64Blob;
EXCEPTION
WHEN OTHERS THEN
RAISE;
END encodeBlob2Base64;
When i now use my function i get the ORA-29261: bad argument in the statement DBMS_LOB.SUBSTR(lob_loc ...)
Has somebody an idea, what's wrong?
Many thanks in advance.
Regards,
Martin

Answer 1

The reason is that utl_encode returns a raw whereas dbms_lob.append expects either a blob or a clob.
SQL> desc utl_encode;
FUNCTION BASE64_DECODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
FUNCTION BASE64_ENCODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
FUNCTION MIMEHEADER_DECODE RETURNS VARCHAR2
Argument Name                  Type                    In/Out Default?
BUF                            VARCHAR2                IN   
FUNCTION MIMEHEADER_ENCODE RETURNS VARCHAR2
Argument Name                  Type                    In/Out Default?
BUF                            VARCHAR2                IN   
ENCODE_CHARSET                 VARCHAR2                IN     DEFAULT
ENCODING                       BINARY_INTEGER          IN     DEFAULT
FUNCTION QUOTED_PRINTABLE_DECODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
FUNCTION QUOTED_PRINTABLE_ENCODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
FUNCTION TEXT_DECODE RETURNS VARCHAR2
Argument Name                  Type                    In/Out Default?
BUF                            VARCHAR2                IN   
ENCODE_CHARSET                 VARCHAR2                IN     DEFAULT
ENCODING                       BINARY_INTEGER          IN     DEFAULT
FUNCTION TEXT_ENCODE RETURNS VARCHAR2
Argument Name                  Type                    In/Out Default?
BUF                            VARCHAR2                IN   
ENCODE_CHARSET                 VARCHAR2                IN     DEFAULT
ENCODING                       BINARY_INTEGER          IN     DEFAULT
FUNCTION UUDECODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
FUNCTION UUENCODE RETURNS RAW
Argument Name                  Type                    In/Out Default?
R                              RAW                     IN   
TYPE                           BINARY_INTEGER          IN     DEFAULT
FILENAME                       VARCHAR2                IN     DEFAULT
PERMISSION                     VARCHAR2                IN     DEFAULT
SQL> spool off