ORA-02437: cannot validate - primary key violated

ORA-02437: cannot validate - primary key violated
====================================================



SQL*Plus: Release 11.1.0.6.0 - Production on Wed Jun 30 16:21:01 2010

Copyright (c) 1982, 2007, Oracle. All rights reserved.

SQL> CONN STLBAS/STLBAS@JUNCLS
Connected.
SQL>
SQL>
SQL> DROP TABLE HALIM_TEST ;

Table dropped.

SQL>
SQL> CREATE TABLE halim_test (id number,name varchar2(30)) ;

Table created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (100,'Mr. Halim');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (100,'Mr Cadot');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (200,'Mr. Arif');

1 row created.

SQL>
SQL>
SQL> INSERT INTO halim_test VALUES (300,'Mr. Akash');

1 row created.

SQL>
SQL> COMMIT;

Commit complete.

SQL>
SQL> ALTER TABLE halim_test ADD PRIMARY KEY (ID) NOVALIDATE ;
ALTER TABLE halim_test ADD PRIMARY KEY (ID) NOVALIDATE
*
ERROR at line 1:
ORA-02437: cannot validate (STLBAS.SYS_C0084074) - primary key violated


SQL>
SQL>
SQL> ALTER TABLE halim_test ADD PRIMARY KEY (ID) DISABLE ;

Table altered.

SQL>
SQL> ALTER TABLE halim_test ENABLE NOVALIDATE PRIMARY KEY;
ALTER TABLE halim_test ENABLE NOVALIDATE PRIMARY KEY
*
ERROR at line 1:
ORA-02437: cannot validate (STLBAS.SYS_C0084075) - primary key violated

SQL>
SQL> ALTER TABLE halim_test ENABLE NOVALIDATE PRIMARY KEY;
ALTER TABLE halim_test ENABLE NOVALIDATE PRIMARY KEY
*
ERROR at line 1:
ORA-02437: cannot validate (STLBAS.SYS_C0084076) - primary key violated



======================
CAUSE & sOLUTION:
======================

This error occurs because it tries to create a unique index for the unique or primary
key index. The uniqueness is checked during the creation of the unique index.


Solution
=============
------- First, create a NON-UNIQUE index on the same fields that you want to
--------include in the constraint.
SQL>
SQL>
SQL> alter table HALIM_TEST drop constraint SYS_C0084076 ;

Table altered.

SQL>
SQL>
SQL> create index IND_ON_HALIM_TEST on halim_test(ID);

Index created.


-------- Then add the unique or primary key constraint.

SQL>
SQL> ALTER TABLE halim_test ADD PRIMARY KEY (ID) NOVALIDATE ;

Table altered.

oR

SQL>
SQL>
SQL> ALTER TABLE HALIM_TEST ENABLE NOVALIDATE PRIMARY KEY;

Table altered.

SQL>
SQL>