Examine the SQL statements that creates ORDERS table:<br /> CREATE TABLE orders<br /> (SER_NO NUMBER UNIQUE,<br /> ORDER_ID NUMBER,<br /> ORDER_DATE DATE NOT NULL<br /> STATUS VARCHARD2(10)<br /> CHECK (status IN ('CREDIT','CASH')),<br /> PROD_ID_NUMBER<br /> REFERENCES PRODUCTS(PRODUCT_ID),<br /> ORD_TOTAL NUMBER,<br /> PRIMARY KEY (order id, order date));<br /> For which columns would an index be automatically created when you execute the aboveSQL statement? ()
A、SER_NO
B、ORDER_ID
C、STATUS
D、PROD_ID
E、ORD_TOTAL
F、Composite index on ORDER_ID and ORDER_DATE