OCP题库：1Z0-051-002题

OCP题库：1Z0-051-002题：完整题库请点击这里联系老师咨询了解

View the Exhibit to examine the description for the SALES table.

Which views can have all DML operations performed on it? (Choose all that apply.)

A. CREATE VIEW v3

AS SELECT * FROM SALES

WHERE cust_id = 2034

WITH CHECK OPTION;

B. CREATE VIEW v1

AS SELECT * FROM SALES

WHERE time_id <= SYSDATE - 2*365

WITH CHECK OPTION;

C. CREATE VIEW v2

AS SELECT prod_id, cust_id, time_id FROM SALES

WHERE time_id <= SYSDATE - 2*365

WITH CHECK OPTION;

D. CREATE VIEW v4

AS SELECT prod_id, cust_id, SUM(quantity_sold) FROM SALES

WHERE time_id <= SYSDATE - 2*365

GROUP BY prod_id, cust_id

WITH CHECK OPTION;

Answer: AB

试题解析：

参考：

C不正确的原因为有其它列不能为空

D出错，sum(quantity_sold)需要加个别名

sh@TESTDB> create view v4

2 as select prod_id,cust_id,sum(quantity_sold) from sales

3 where time_id<=sysdate-2*365

4 group by prod_id,cust_id

5 with check option

6 ;

as select prod_id,cust_id,sum(quantity_sold) from sales

ERROR at line 2:

ORA-00998: must name this expression with a column alias

sh@TESTDB> create view v4

2 as select prod_id,cust_id,sum(quantity_sold) sumqty from sales

3 where time_id<=sysdate-2*365

4 group by prod_id,cust_id

5 with check option

6 ;