How to temporarily disable on delete cascade but not the constraint

Question

Hi all
i would like to know if this is possible
how to temporarily disable on delete cascade but not the constraint
i want to delete a row from the primary key table but i dont want the data from the foreign key to be deleted even though there is an on delete cascade set.
how do i temporarily disable on delete cascade from firing without disabling the constraint
Rgrds

Answer 1

There is an option which I've never used before but just read about which is to create your foreign key constraint as on delete SET NULL
instead of on delete cascade.
This will allow you to delete a parent and will set the foreign key column values in the child table to nulls
e.g.
SQL> create table parent (father varchar2(30) primary key,
  2                       age number);
Table created.
SQL>
SQL> create table child (father varchar2(30) constraint fk references parent(father) on delete set null,
  2                      child varchar2(30),
  3                      age number);
Table created.
SQL>                    
SQL> insert into parent values ('JOHN', 34);
1 row created.
SQL> insert into child values ('JOHN', 'SARAH', 10);
1 row created.
SQL> insert into child values ('JOHN', 'BILL', 12);                   
1 row created.
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> delete from parent where father = 'JOHN';
1 row deleted.
SQL>
SQL> select * from child;
FATHER                         CHILD                                 AGE
                               SARAH                                  10
                               BILL                                   12
SQL> HTH AMM