Problem arises adding unique constraint

Question

Dear all
The problem I am facing while adding a unique constraint(based on 2 columns) is ,the table has already duplicate records.I am unable to delete those duplicate records as it has several child record table and those child tables are parent of another table.....and so on. I dont want to use ON DELETE CASCADE.any kind of suggestion?

Answer 1

Hi,
If you want to delete the duplicates you can but that is upto you.
You can delete the duplicate rows by disabling all foreign key constraints.
SQL> ED
Wrote file afiedt.buf
  1  select constraint_name,constraint_type,STATUS
  2  from user_constraints
  3* where table_name='EMP'
SQL> /
CONSTRAINT_NAME                C STATUS
PK_EMP                         P ENABLED
FK_DEPTNO                      R ENABLED
SQL> ALTER TABLE EMP DISABLE CONSTRAINT FK_DEPTNO;
Table altered.
SQL> select constraint_name,constraint_type,STATUS
  2  from user_constraints
  3  where table_name='EMP'
  4  ;
CONSTRAINT_NAME                C STATUS
PK_EMP                         P ENABLED
FK_DEPTNO                      R DISABLED-San
Edited by: san on Feb 24, 2011 1:02 PM