SQL>
SQL> CREATE TABLE person (
2 person_code VARCHAR2(3) PRIMARY KEY,
3 first_name VARCHAR2(15),
4 last_name VARCHAR2(20),
5 hire_date DATE
6 );
Table created.
SQL>
SQL> ALTER TABLE person
2 ADD CONSTRAINT person_unique UNIQUE (
3 first_name,
4 last_name,
5 hire_date
6 );
Table altered.
SQL>
SQL> drop table person;
Table dropped.
SQL>