SQL> describe Room;   
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ROOMNAME                                  NOT NULL VARCHAR2(20)
 ROOMLOCATION                                       VARCHAR2(20)

SQL> describe Activity;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 ACTMODCODE                                NOT NULL CHAR(6)
 ACTDESCRIPTION                            NOT NULL VARCHAR2(10)

SQL> describe Schedule;
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 SCHSLOT                                   NOT NULL VARCHAR2(10)
 ROOMNAME                                           VARCHAR2(20)
 ACTMODCODE                                         CHAR(6)
 ACTDESCRIPTION                                     VARCHAR2(10)

SQL> select * from Room;

ROOMNAME             ROOMLOCATION
-------------------- --------------------
JC-EXCHGE-C.LT2      Exchange
JC-EXCHGE-D.LT3      Exchange
JC-EXCHGE-COMP-A32   Computer Science

SQL> select * from Activity;

ACTMODCODE ACTDESCRIPTION
---------- --------------
G51DBS     Lab
G51DBS     Lecture1
G51DBS     Lecture2
G51PRG     Lab
G51PRG     Lecture1
G51PRG     Lecture2

6 rows selected.

SQL> select * from Schedule;

SCHSLOT    ROOMNAME             ACTMODCODE ACTDESCRIPTION
---------- -------------------- ---------- --------------
Mon 9-10   JC-EXCHGE-C.LT2      G51DBS     Lecture1
Mon 10-11  JC-EXCHGE-C.LT2      G51PRG     Lecture1
Tue 13-14  JC-EXCHGE-C.LT2      G51PRG     Lecture2
Tue 14-16  JC-EXCHGE-COMP-A32   G51PRG     Lab
Wed 9-11   JC-EXCHGE-COMP-A32   G51DBS     Lab
Wed 12-13  JC-EXCHGE-D.LT3      G51DBS     Lecture2

6 rows selected.