Examine the SQL statement that creates ORDERS table:
CREATE TABLE orders (SER_NO NUMBER UNIQUE, ORDER_ID NUMBER, ORDER_DATE
DATE NOT NULL, STATUS VARCHAR2(10) CHECK (status IN (‘CREDIT’, ‘CASH’)), PROD_ID
NUMBER REFERENCES PRODUCTS(PRODUCT_ID), ORD_TOTAL NUMBER, PRIMARY KEY
(order_id, order_date));
For which columns would an index be automatically created when you execute the above SQL
statement? (Choose two.)
A.
SER_NO
B.
ORDER_ID
C.
STATUS
D.
PROD_ID
E.
ORD_TOTAL
F.
composite index on ORDER_ID and ORDER_DATE
Explanation:
Index exist for UNIQUE and PRIMARY KEY constraints
Incorrect answer:
BORDER_ID is neither UNIQUE nor PRIMARY KEY
CSTATUS is neither UNIQUE nor PRIMARY KEY
DPROD_ID is neither UNIQUE nor PRIMARY KEY
EORD_TOTAL is neither UNIQUE nor PRIMARY KEY
Refer: Introduction to Oracle9i: SQL, Oracle University Study Guide, 10-15