SQL>
SQL>
SQL> create table subjects (
2 subject_id number not null,
3 subject_name varchar2(30) not null,
4 description varchar2(4000)
5 )
6 tablespace users;
Table created.
SQL>
SQL> alter table subjects
2 add constraint pk_subjects primary key (subject_id);
Table altered.
SQL>
SQL> drop table subjects;
Table dropped.
SQL>