EXEC SQL DECLARE cur_num CURSOR FOR
                 SELECT STUDENT_NUMBER
                   FROM STUDENTS
                  WHERE STDID = :temp_num
               ORDER BY STUDENT_NUMBER;

        EXEC SQL OPEN cur_num;

        EXEC SQL WHENEVER NOT FOUND DO break;

        EXEC SQL WHENEVER SQLERROR DO sqlerror();

        for(;;)
        {
           EXEC SQL FETCH cur_num INTO :std_num ;

	   /* Some calculations here */


           EXEC SQL INSERT INTO RESULTS(STUDENT_NUMBER,
                                        SUBJECT,
                                        MARKS)
                                 VALUES(:std_num,
                                        :sub,
                                        :marks);

           EXEC SQL COMMIT;        

        }

        EXEC SQL CLOSE cur_num;

ORA-01002: fetch out of sequence
 *Cause: This error means that a fetch has been attempted from a cursor
         which is no longer valid.  Note that a PL/SQL cursor loop
         implicitly does fetches, and thus may also cause this error.
         There are a number of possible causes for this error, including:
         1) Fetching from a cursor after the last row has been retrieved
            and the ORA-1403 error returned.
         2) If the cursor has been opened with the FOR UPDATE clause,
            fetching after a COMMIT has been issued will return the error.
         3) Rebinding any placeholders in the SQL statement, then issuing
            a fetch before reexecuting the statement.
 *Action: 1) Do not issue a fetch statement after the last row has been
             retrieved - there are no more rows to fetch.
          2) Do not issue a COMMIT inside a fetch loop for a cursor
             that has been opened FOR UPDATE.
          3) Reexecute the statement after rebinding, then attempt to
             fetch again.