Adding the Unique Constraint after Table Creation:

 

1. Adding the Unique Constraint after Table Creation:

If you’ve already created the REGISTER_BOOK table and want to add the unique constraint to the RB_NUMBER column, you can run the following ALTER TABLE command:

sql
ALTER TABLE "REGISTER_BOOK"
ADD CONSTRAINT "REGISTER_BOOK_RB_NUMBER_UK" UNIQUE ("RB_NUMBER");