Concatenating BLOB data in PL/SQL, returning it to Pro*C

I may be going about this in entirely the wrong way, but ...

I have a database containing blob data. I wish to write a PL/SQL stored function which can be called from Pro*C.

I would like this stored procedure to collect the data from blobs stored in several rows and return it in some parseable form to my C program.

Several hours with enormous manuals later, and I'm thinking this is not an easy problem. Some sample code follows; in particular, what I want is for something like the CONCAT to work, looping over each row collecting blob data into some form which is returned to the caller.

Any thoughts?

Thanks,
--chuck

CREATE OR REPLACE FUNCTION goober
RETURN RAW IS     blob_locator BLOB;

    offset               NUMBER := 1;
    buffer               RAW(1000);
    rval                 RAW(10000);
    length               NUMBER := 0;
    b_ptr                NUMBER := 0;
    continue             NUMBER := 0;

    CURSOR        csr_get_id IS SELECT widgit from widgits;
    CURSOR        csr_get_locator(in_id NUMBER) IS SELECT widgit_data from
                          our.wigits where widgit_id = in_id;

BEGIN
    OPEN csr_get_id;

        LOOP

            FETCH csr_get_id INTO id;
            EXIT WHEN csr_get_id%NOTFOUND;
            OPEN csr_get_locator(id);

            FETCH csr_get_locator INTO blob_locator;

            IF csr_get_locator%FOUND THEN
                length := DBMS_LOB.GETLENGTH(blob_locator);

                IF length > 0 THEN
                    DBMS_LOB.READ(blob_locator, length, offset, buffer);


                    -- ***


                    -- It would be sooooo cool if this next line worked.


                    -- ***


		    rval := CONCAT (rval, buffer);

                END IF;
                CLOSE csr_get_locator;

            ELSE
                CLOSE csr_get_locator;
            END IF;

        END LOOP;
        CLOSE csr_get_id;
        RETURN rval;

-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Thu Jan 21 1999 - 13:28:19 CST