1.实验目的
掌握数据库存储过程的设计和使用方法。
2.实验内容和要求
存储过程的定义,存储过程运行,存储过程更名,存储过程删除。
3.实验步骤和实验结果
(1)定义一个存储过程 proc1,更新所有订单(含税折扣价)的总价,执行这个存储过程:
创建存储过程:
```sql
CREATE PROCEDURE proc1 () BEGIN
UPDATE orders
SET totalprice =(
SELECT
SUM(
extendedprice *(
1+tax
)*(
1-discount
))
FROM
lineitem
WHERE
orders.orderkey = lineitem.orderkey
);
END;
调用存储过程:
CALL proc1;
查看:
实验前数据:
实验后数据:
(2)定义一个存储过程 proc2,更新给定订单的(含税折扣价)的总价,执行这个存储过程:
创建存储过程:
CREATE PROCEDURE proc2 ( IN okey INT ) BEGIN
UPDATE orders
SET totalprice =(
SELECT
SUM( extendedprice *( 1+tax )*( 1-discount ) )
FROM
lineitem
WHERE
orders.orderkey = lineitem.orderkey
);
END;
调用存储过程:
CALL proc2(20);
(3)定义一个存储过程 proc3,更新某个顾客的所有订单的(含税折扣价)总价,执行这个存储过程:
创建存储过程:
CREATE PROCEDURE proc3 ( IN cname INT ) BEGIN
DECLARE
ckey INT;
SELECT
custkey INTO ckey
FROM
customer
WHERE
customer.NAME = cname;
UPDATE orders
SET totalprice =(
SELECT
SUM(
extendedprice *(
1+tax
)*(
1-discount
))
FROM
lineitem,
orders
WHERE
lineitem.orderkey = orders.orderkey
AND orders.custkey = ckey
);
END;
调用:
首先根据orderkey找到一个顾客名用做调用存储过程的参数值:
CALL proc3(‘孔珍’);
(4)定义一个存储过程 proc4,更新某个顾客的所有订单的(含税折扣价)总价并输出该总价,执行这个存储过程:
创建存储过程:
CREATE PROCEDURE proc4 (
IN cname CHAR ( 25 ),
OUT tprice DECIMAL ( 10, 2 )) BEGIN
DECLARE
ckey INT;
SELECT
custkey INTO ckey
FROM
customer
WHERE
NAME = cname;
UPDATE orders
SET totalprice =(
SELECT
SUM(
extendedprice *(
1+tax
)*(
1-discount
))
FROM
lineitem
WHERE
lineitem.orderkey = orders.orderkey
);
SELECT
SUM( totalprice ) INTO tprice
FROM
orders
WHERE
orders.custkey = ckey
GROUP BY
orderkey;
END;
调用:
查看:
(5)删除存储过程 proc4:
DROP PROCEDURE proc4;
查看:
(6)定义一个存储过程 proc5,更新某年订单(含税折扣价)的总价,执行这个存储过程。(要求使用游标完成):
创建存储过程:
CREATE PROCEDURE proc5 () BEGIN
DECLARE
cursor_price DECIMAL ( 10, 2 );#记录某一个totalprice
DECLARE
cursor_extendedprice DECIMAL ( 8, 2 );
DECLARE
cursor_discount DECIMAL ( 3, 2 );
DECLARE
cursor_tax DECIMAL ( 3, 2 );
DECLARE
cursor1 CURSOR FOR SELECT
extendedprice
FROM
lineitem,
orders
WHERE
orders.orderkey = lineitem.orderkey;
DECLARE
cursor2 CURSOR FOR SELECT
discount
FROM
lineitem,
orders
WHERE
orders.orderkey = lineitem.orderkey;
DECLARE
cursor3 CURSOR FOR SELECT
tax
FROM
lineitem,
orders
WHERE
orders.orderkey = lineitem.orderkey;
OPEN cursor1;
OPEN cursor2;
OPEN cursor3;
FETCH cursor1 INTO cursor_extendedprice;
FETCH cursor2 INTO cursor_discount;
FETCH cursor3 INTO cursor_tax;
SET cursor_price = cursor_extendedprice *(
1+cursor_tax
)*(
1-cursor_discount
);
CLOSE cursor1;
CLOSE cursor2;
CLOSE cursor3;
SELECT
SUM( totalprice )
FROM
orders
WHERE
YEAR ( orderdate )= 2022;
END;
查看:
(7)定义一个存储过程 proc6,能够根据某年(年份作为输入参数,整数)各个客户的下订单购买情况,把该年客户订单总金额超过某个阈值(该阈值为输入参数,为整数)的客户表(customer)中的备注(comment)字段更新为重要客户(“SVIP”)(要求使用游标完成):
创建存储过程:
CREATE PROCEDURE proc6 ( IN YEAR INT, IN threshold INT ) BEGIN
DECLARE
price DECIMAL ( 10, 2 );
DECLARE
cursor_comment VARCHAR ( 100 );
DECLARE
cursor1 CURSOR FOR SELECT COMMENT
FROM
customer
WHERE
custkey IN ( SELECT custkey FROM orders );
DECLARE
cursor2 CURSOR FOR SELECT
totalprice
FROM
orders
WHERE
YEAR ( orderdate )= YEAR
AND custkey IN ( SELECT custkey FROM customer );
OPEN cursor1;
OPEN cursor2;
FETCH cursor1 INTO cursor_comment;
FETCH cursor2 INTO price;
IF
price >= threshold THEN
SET cursor_comment = 'SVIP';
END IF;
CLOSE cursor1;
END;
查看: