You created an ORDERS table with the following description:
name Null Type
ORD_ID NOT NULL NUMBER(2)
CUST_ID NOT NULL NUMBER(3)
ORD_DATE NOT NULL DATE
ORD_AMOUNT NOT NULL NUMBER (10,2)
You inserted some rows in the table. After some time, you want to alter the table by creating the PRIMARY
KEY constraint on the ORD_ID column. Which statement is true in this scenario?
A.
You cannot have two constraints on one column.
B.
You cannot add a primary key constraint if data exists in the column.
C.
The primary key constraint can be created only at the time of table creation .
D.
You can add the primary key constraint even if data exists, provided that there are no duplicate values.