DECLARE
   v_status     CHAR (1) := 'N';
   v_courseid   NUMBER;
   a            NUMBER;
BEGIN
   IF :exam_date IS NULL
   THEN
      MESSAGE ('enter the Exam date');
   ELSIF :course IS NULL
   THEN
      MESSAGE ('select the coursename');
   ELSIF :exam_paper IS NULL
   THEN
      MESSAGE ('select the exam paper');
   END IF;

   SELECT course_id
     INTO v_courseid
     FROM online_course
    WHERE course = :block3.course 
    AND exam_paper = :block3.exam_paper;

   IF :exam_date > TRUNC (SYSDATE)
   THEN
      INSERT INTO onlin_enroll
                  (exam_id, user_name, course_id, exam_date,
                   enrollment_date, status
                  )
           VALUES (exa_id_seq.NEXTVAL, :GLOBAL.abc, v_courseid, :exam_date,
                   SYSDATE, v_status
                  );

      COMMIT;
   ELSIF :exam_date = TRUNC (SYSDATE)
   THEN
      INSERT INTO onlin_enroll
                  (exam_id, user_name, course_id, exam_date,
                   enrollment_date, status
                  )
           VALUES (exa_id_seq.NEXTVAL, :GLOBAL.abc, v_courseid, :exam_date,
                   SYSDATE, v_status
                  );

      
      CALL_FORM ('E:\online1\qns1');
      COMMIT;
   ELSIF :exam_date < TRUNC (SYSDATE)
   THEN
      a := SHOW_ALERT ('alert_exam');
  
     
   END IF;
END;

select exa_id_seq.currval
into :global.exa
from dual;