How to name the constraint when add NOT NULL on ALTER TABLE

Question

ALTER TABLE ACTOR MODIFY FIRST_NAME VARCHAR2(45) NOT NULL;

I know have to set FIST_NAME to NOT NULL, but I don not know how to name this constraint.

The name of this constraint should be "CK_Fanme"

Answer 1

You can use

ALTER TABLE actor MODIFY ( first_name CONSTRAINT not_null_first_name NOT NULL );

and query to see the result through use of user_constraints data dictionary view such as

SELECT constraint_name
  FROM user_constraints
 WHERE table_name = 'ACTOR'

Demo