View the Exhibit button and examine the structures of ORDERS and ORDER_ITEMS
tables. In the ORDERS table, ORDER_ID is the PRIMARY KEY and in the ORDER_ITEMS
table, ORDER_ID and LINE_ITEM_ID form the composite primary key. Which view can
have all the DML operations performed on it?
A.
CREATE VIEW V1 AS SELECT order_id, product_id FROM order_items;
B.
CREATE VIEW V2 AS SELECT order_id, line_item_id, unit_price*quantity total FROM
order items;
C.
CREATE VIEW V4(or_no, or_date, cust_id) AS SELECT order_id, order_date,
customer_id FROM orders WHERE order_date < 30-mar-2007′ WITH CHECK OPTION;
D.
CREATE VIEW V3 AS SELECT o.order_id, o.customer_id, i.product_id FROM orders o,
order_items i WHERE o.order_id=i. order_id;
A is incorrect because order_items is not a key preserved table in the view.