You have an ORDERS table with the following structure: Name Null?

You have an ORDERS table with the following structure: Name Null? Type
————————- ——– ————————- OID NUMBER(6) ODATE DATE CCODE
NUMBER(6) OAMT NUMBER(10,2) The table has data in the ODATE column for all rows.
Many orders are placed in a single day. You need to ensure that the ODATE column must
contain data for every order in future. Which method would serve the purpose?

A.
Add a UNIQUE constraint to the column using the ALTER TABLE…ADD CONSTRAINT
command.

B.
Add a PRIMARY KEY constraint to the column using the ALTER TABLE…ADD
CONSTRAINT command.

C.
Modify the column using the ALTER TABLE…MODIFY command.

D.
Add a NOT NULL constraint to the column using the ALTER TABLE…ADD
CONSTRAINT command.