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SQL> CREATE TABLE rooms (
2 room_id NUMBER(5) PRIMARY KEY,
3 building VARCHAR2(15),
4 room_number NUMBER(4),
5 number_seats NUMBER(4),
6 description VARCHAR2(50)
7 );
Table created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20001, 'Building 7', 201, 1000, 'Large Lecture Hall');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20002, 'Building 6', 101, 500, 'Small Lecture Hall');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20003, 'Building 6', 150, 50, 'Discussion Room A');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20004, 'Building 6', 160, 50, 'Discussion Room B');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats,description)
2 VALUES (20005, 'Building 6', 170, 50, 'Discussion Room C');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20006, 'Music Building', 100, 10, 'Music Practice Room');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20007, 'Music Building', 200, 1000, 'Concert Room');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats, description)
2 VALUES (20008, 'Building 7', 300, 75, 'Discussion Room D');
1 row created.
SQL>
SQL> INSERT INTO rooms (room_id, building, room_number, number_seats,description)
2 VALUES (20009, 'Building 7', 310, 50, 'Discussion Room E');
1 row created.
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 OR REPLACE VIEW session_rooms AS
2 SELECT department, course, building, room_number
3 FROM rooms, session
4 WHERE rooms.room_id = session.room_id;
View created.
SQL>
SQL> SELECT * FROM session_rooms;
DEP COURSE BUILDING ROOM_NUMBER
--- ---------- --------------- -----------
HIS 301 Building 6 160
CS 101 Building 7 201
ECN 203 Building 6 101
CS 102 Building 6 150
MUS 410 Building 6 170
ECN 101 Music Building 200
NUT 307 Building 7 300
7 rows selected.
SQL>
SQL> CREATE TRIGGER sessionRoomsInsert
2 INSTEAD OF INSERT ON session_rooms
3 DECLARE
4 v_roomID rooms.room_id%TYPE;
5 BEGIN
6 SELECT room_id
7 INTO v_roomID
8 FROM rooms
9 WHERE building = :new.building
10 AND room_number = :new.room_number;
11
12 UPDATE session
13 SET room_id = v_roomID
14 WHERE department = :new.department
15 AND course = :new.course;
16 END sessionRoomsInsert;
17 /
Trigger created.
SQL>
SQL> INSERT INTO session_rooms (department, course, building, room_number)
2 VALUES ('MUS', 100, 'Music Building', 200);
1 row created.
SQL>
SQL> SELECT * FROM session_rooms;
DEP COURSE BUILDING ROOM_NUMBER
--- ---------- --------------- -----------
HIS 301 Building 6 160
CS 101 Building 7 201
ECN 203 Building 6 101
CS 102 Building 6 150
MUS 410 Building 6 170
ECN 101 Music Building 200
NUT 307 Building 7 300
MUS 100 Music Building 200
8 rows selected.
SQL>
SQL> drop view session_rooms;
View dropped.
SQL> drop table session;
Table dropped.
SQL> drop table rooms;
Table dropped.
SQL>
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