Violate an unique constraints : Unique « Table « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. Table
3. Unique

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>
SQL>
SQL> INSERT INTO person VALUES ('CA', 'Chase', 'At', '01-FEB-02');

1 row created.

SQL> INSERT INTO person VALUES ('GA', 'Chase', 'At', '01-FEB-02');
INSERT INTO person VALUES ('GA', 'Chase', 'At', '01-FEB-02')
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.PERSON_UNIQUE) violated


SQL> INSERT INTO person VALUES ('BB', 'Bob', 'Bark', '28-FEB-02');

1 row created.

SQL> INSERT INTO person VALUES ('LB', 'Laren', 'Baby', '01-MAR-02');

1 row created.

SQL> INSERT INTO person VALUES ('LN', 'Linda', 'Norman', '01-JUN-03');

1 row created.

SQL>
SQL> select * from person;

PER FIRST_NAME      LAST_NAME            HIRE_DATE
--- --------------- -------------------- ---------
CA  Chase           At                   01-FEB-02
BB  Bob             Bark                 28-FEB-02
LB  Laren           Baby                 01-MAR-02
LN  Linda           Norman               01-JUN-03

SQL>
SQL> drop table person;

Table dropped.

SQL>
SQL>