MySQL第五次作业-优快云博客

本文链接：https://blog.youkuaiyun.com/2201_75406597/article/details/145521074

题目要求：

1、触发器

(1)在数据库mydb16_trigger中建立goods和orders表：

mysql> create table goods(
    -> gid char(8) primary key,
    -> name varchar(10),
    -> price decimal(8,2),
    -> num int);
Query OK, 0 rows affected (0.04 sec)
mysql> create table orders(
    -> oid int primary key auto_increment,
    -> gid  char(10)  not null,
    -> name varchar(10),
    -> price  decimal(8,2),
    -> onum int,
    -> otime date);
Query OK, 0 rows affected (0.03 sec)

（2）使用desc查看表结构：

mysql> desc goods;
+-------+--------------+------+-----+---------+-------+
| Field | Type         | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| gid   | char(8)      | NO   | PRI | NULL    |       |
| name  | varchar(10)  | YES  |     | NULL    |       |
| price | decimal(8,2) | YES  |     | NULL    |       |
| num   | int          | YES  |     | NULL    |       |
+-------+--------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
mysql> desc orders;
+-------+--------------+------+-----+---------+----------------+
| Field | Type         | Null | Key | Default | Extra          |
+-------+--------------+------+-----+---------+----------------+
| oid   | int          | NO   | PRI | NULL    | auto_increment |
| gid   | char(10)     | NO   |     | NULL    |                |
| name  | varchar(10)  | YES  |     | NULL    |                |
| price | decimal(8,2) | YES  |     | NULL    |                |
| onum  | int          | YES  |     | NULL    |                |
| otime | date         | YES  |     | NULL    |                |
+-------+--------------+------+-----+---------+----------------+
6 rows in set (0.00 sec)

(3)在orders表中插入数据：

mysql> insert into goods values
    -> ('A0001','橡皮',2.5,100),
    -> ('B0001','小楷本',2.8,210),
    -> ('C0001','铅笔',1.2,120),
    -> ('D0001','计算器',28,20);
Query OK, 4 rows affected (0.01 sec)
Records: 4  Duplicates: 0  Warnings: 0
mysql> select * from goods;
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |  100 |
| B0001 | 小楷本 |  2.80 |  210 |
| C0001 | 铅笔   |  1.20 |  120 |
| D0001 | 计算器 | 28.00 |   20 |
+-------+--------+-------+------+
4 rows in set (0.00 sec)

（3）建立触发器，订单表中增加订单数量后，商品表商品数量同步减少对应的商品订单出数量,并测试

mysql> delimiter //
mysql> create trigger update_goods_after_insert_order
    -> after insert on orders
    -> for each row
    -> begin
    ->          update goods set num =  num - new.onum where gid = new.gid;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（4）建立触发器，实现功能:客户取消订单，恢复商品表对应商品的数量

mysql> create trigger update_goods_after_delete_order
    -> after delete on orders
    -> for each row
    -> begin
    ->          update goods set num = num + old.onum where gid = old.gid;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（5）建立触发器，实现功能:客户修改订单，商品表对应商品数量同步更新

mysql> create trigger update_goods_after_update_order
    -> after update on orders
    -> for each row
    -> begin
    ->          update goods set num = num + old.onum - new.onum where gid = new.gid;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（6）测试

在orders表中插入一条新的订单记录：

insert into orders (gid, name, price, onum, otime) values ('A0001', '橡皮', 2.5, 20, curdate());

查询goods表的全部内容：

mysql> select * from goods;
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |   80 |
| B0001 | 小楷本 |  2.80 |  210 |
| C0001 | 铅笔   |  1.20 |  120 |
| D0001 | 计算器 | 28.00 |   20 |
+-------+--------+-------+------+
4 rows in set (0.00 sec)

在orders表中删除一条订单记录：

mysql> delete from orders where oid = 1;
Query OK, 1 row affected (0.01 sec)
#查询goods表表中橡皮的数量
mysql> select * from goods;
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |  100 |
| B0001 | 小楷本 |  2.80 |  210 |
| C0001 | 铅笔   |  1.20 |  120 |
| D0001 | 计算器 | 28.00 |   20 |
+-------+--------+-------+------+
4 rows in set (0.00 sec)

更新一条订单记录：

mysql> select * from goods;
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |   80 |
| B0001 | 小楷本 |  2.80 |  210 |
| C0001 | 铅笔   |  1.20 |  120 |
| D0001 | 计算器 | 28.00 |   20 |
+-------+--------+-------+------+
4 rows in set (0.00 sec)
mysql> select * from orders;
+-----+-------+------+-------+------+------------+
| oid | gid   | name | price | onum | otime      |
+-----+-------+------+-------+------+------------+
|   2 | A0001 | 橡皮 |  2.50 |   20 | 2025-02-08 |
+-----+-------+------+-------+------+------------+
1 row in set (0.00 sec)
mysql> update orders set onum = 9 where oid = 2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql> select * from goods;
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |   91 |
| B0001 | 小楷本 |  2.80 |  210 |
| C0001 | 铅笔   |  1.20 |  120 |
| D0001 | 计算器 | 28.00 |   20 |
+-------+--------+-------+------+
4 rows in set (0.00 sec)

2、存储过程

（1）使用数据库表：

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb10_city        |
| mydb12_journal     |
| mydb13_indexdb     |
| mydb14_job         |
| mydb15_indexstu    |
| mydb16_trigger     |
| mydb1_test         |
| mydb2_stuinfo      |
| mydb3_employee     |
| mydb4_product      |
| mydb5_sales        |
| mydb6_product      |
| mydb7_openlab      |
| mydb8_worker       |
| mydb9_stusys       |
| mydb_temp1         |
| mydbx_temp3        |
| mysql              |
| mysql_test         |
| performance_schema |
| sys                |
| temp1              |
+--------------------+
23 rows in set (0.00 sec)

mysql> use mydb7_openlab;
Database changed

（2）创建提取emp_new表所有员工姓名和工资的存储过程s1

mysql> delimiter //
mysql> create procedure s1()
    -> begin
    ->          select name, incoming as salary from emp_new;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（3）创建存储过程s2，实现输入员工姓名后返回员工的年龄

mysql> create procedure s2(in p_name varchar(50), out p_age int)
    -> begin
    ->          select age into p_age from emp_new where name = p_name;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（4）创建一个存储过程s3，有2个参数，传入部门号，返回该部门的平均工资

mysql> create procedure s3(in p_dept int, out p_avg_salary decimal(10,2))
    -> begin
    ->          select avg(incoming) into p_avg_salary from emp_new where dept2 = p_dept;
    -> end //
Query OK, 0 rows affected (0.01 sec)

（5）测试

s1：

mysql> delimiter ;
mysql> call s1();
+------+--------+
| name | salary |
+------+--------+
| 张三 |   4000 |
| 李四 |   3500 |
| 王五 |   2000 |
| 赵六 |   7500 |
| 荣七 |   8500 |
| 牛八 |   7300 |
+------+--------+
6 rows in set (0.00 sec)

Query OK, 0 rows affected (0.01 sec)

s2：

mysql> call s2('张三',@age);
Query OK, 1 row affected (0.00 sec)

mysql> select @age
    -> ;
+------+
| @age |
+------+
|   35 |
+------+
1 row in set (0.00 sec)

s3：

mysql> call s3(102,@avg);
Query OK, 1 row affected (0.00 sec)

mysql> select @avg;
+---------+
| @avg    |
+---------+
| 8000.00 |
+---------+
1 row in set (0.00 sec)