SQL & PL/SQL

DB Version:10gR2

In the below example, i have a self referencing foreign key mgr. When i DELETE records
i don't get an ORA-02292 error from the self referencing FK.

create table emp2 
 (
 empno number primary key,
 mgr   number references emp2( empno )
 );

Table created.



INSERT INTO EMP2 VALUES (2,2);

INSERT INTO EMP2 VALUES(3,NULL);

INSERT INTO EMP2 VALUES (4,3);

COMMIT;

SQL>DELETE FROM EMP2;

3 rows deleted.

But in one of our Production tables which has a self referential FK, i get an error similair to

ERROR at line 1:
ORA-02292: integrity constraint (SCOTT.EMP2_FK) violated - child record found

when i try to delete records.Any idea why i am getting this error?