SQL>
SQL> CREATE TABLE session (
2 department CHAR(3),
3 course NUMBER(3),
4 description VARCHAR2(2000),
5 max_lecturer NUMBER(3),
6 current_lecturer NUMBER(3),
7 num_credits NUMBER(1),
8 room_id NUMBER(5)
9 );
Table created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('HIS', 101, 'History 101', 30, 11, 4, 20000);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('HIS', 301, 'History 301', 30, 0, 4, 20004);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('CS', 101, 'Computer Science 101', 50, 0, 4, 20001);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('ECN', 203, 'Economics 203', 15, 0, 3, 20002);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('CS', 102, 'Computer Science 102', 35, 3, 4, 20003);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('MUS', 410, 'Music 410', 5, 4, 3, 20005);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('ECN', 101, 'Economics 101', 50, 0, 4, 20007);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('NUT', 307, 'Nutrition 307', 20, 2, 4, 20008);
1 row created.
SQL>
SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ('MUS', 100, 'Music 100', 100, 0, 3, NULL);
1 row created.
SQL>
SQL>
SQL> CREATE TABLE myLogTable (
2 code NUMBER,
3 message VARCHAR2(200),
4 info VARCHAR2(100)
5 );
Table created.
SQL>
SQL>
SQL>
SQL> DECLARE
2 myException EXCEPTION;
3 studentCount NUMBER(3);
4 studentMax NUMBER(3);
5
6 v_ErrorCode NUMBER;
7 v_ErrorText VARCHAR2(200);
8
9 BEGIN
10 SELECT current_lecturer, max_lecturer
11 INTO studentCount, studentMax
12 FROM session
13 WHERE department = 'HIS' AND course = 101;
14 IF studentCount > studentMax THEN
15 RAISE myException;
16 END IF;
17 EXCEPTION
18 WHEN myException THEN
19 INSERT INTO myLogTable (info) VALUES ('History 101 has ' || studentCount ||
20 'lecturer: max allowed is ' || studentMax);
21 WHEN OTHERS THEN
22 v_ErrorCode := SQLCODE;
23 v_ErrorText := SUBSTR(SQLERRM, 1, 200); -- Note the use of SUBSTR here.
24 INSERT INTO myLogTable (code, message, info) VALUES
25 (v_ErrorCode, v_ErrorText, 'Oracle error occurred');
26 END;
27 /
PL/SQL procedure successfully completed.
SQL>
SQL> drop table session;
Table dropped.
SQL> drop table myLogTable;
Table dropped.
SQL>