Using a Deferred Constraint in Oracle

ALTER TABLE DEPARMENTS
ADD CONSTRAINT fk1
FOREIGN KEY (RF_USER_ID)
REFERENCES USERS (ID) DEFERRABLE;


set constraint FK1 deferred;

update users
set ID = 5
where ID = 2;

update deparments
set RF_USER_ID = 5
where ID = 1;

commit;

OR

 

SET CONSTRAINT FK1 IMMEDIATE;