Create constraint in alter table without checking existing data

Question

I\'m trying to create a constraint on the OE.PRODUCT_INFORMATION table which is delivered with Oracle 11g R2. The constraint should make the PRODUCT

Answer 1

You can use deferrable .

ALTER TABLE PRODUCT_INFORMATION
  ADD CONSTRAINT PRINF_NAME_UNIQUE UNIQUE (PRODUCT_NAME)
deferrable initially deferred NOVALIDATE;