SQL>
SQL> CREATE TABLE person (
2 person_code VARCHAR2(3),
3 first_name VARCHAR2(15),
4 last_name VARCHAR2(20),
5 hire_date DATE
6 );
Table created.
SQL>
SQL>
SQL>
SQL> ALTER TABLE person MODIFY (first_name NOT NULL);
Table altered.
SQL> ALTER TABLE person MODIFY (last_name NOT NULL);
Table altered.
SQL>
SQL> INSERT INTO person VALUES ('XL', 'Xaviera', NULL, '15-NOV-03');
INSERT INTO person VALUES ('XL', 'Xaviera', NULL, '15-NOV-03')
*
ERROR at line 1:
ORA-01400: cannot insert NULL into ("RNTSOFT"."PERSON"."LAST_NAME")
SQL>
SQL> drop table person;
Table dropped.
SQL>
SQL>