Mysql作业5

原创已于 2025-11-12 23:12:09 修改 · 188 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#mysql #android #数据库

于 2025-11-07 23:10:28 首次发布

一、触发器

1、建立两个表:goods (商品表)、orders(订单表)

mysql> create database mydb16_trigger;

mysql> use mydb16_trigger;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> create table goods
    -> (gid char(8) primary key,
    -> name varchar(10),
    -> price decimal(8,2),
    -> num int);
Query OK, 0 rows affected (0.02 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 (0.02 sec)

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 (0.00 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)

2、在商品表中导入商品记录

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','计算机',28,20);

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 | 计算机    | 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测试

mysql> insert into orders(gid,name,price,onum,otime) values('A0001','橡皮',2.50,20,now());
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   1 | A0001 | 橡皮   |  2.50 |   20 | 2025-11-11 |
+-----+-------+--------+-------+------+------------+
1 row in set (0.00 sec)

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> delimiter //
mysql> create trigger trg_order_insert 
    -> after insert on orders for each row
    -> begin
    -> update goods set num = num - new.onum where gid = new.gid;
    -> end //
mysql> delimiter ;
mysql> insert into orders (gid, name, price, onum, otime)
    -> values ('a0001', '橡皮', 2.50, 10, '2025-11-07 10:00:00');
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> select * from goods where gid = 'a0001';
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |   90 |
+-------+--------+-------+------+
1 row in set (0.00 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  orders_delete_after_trigger
    -> after  delete  on  orders
    -> for  each row
    -> update  goods  set  num=num+old.onum  where  gid = old.gid ;
Query OK, 0 rows affected (0.01 sec)

mysql> delete from orders where gid='A0001';
Query OK, 1 row affected (0.00 sec)

mysql> select * from orders;
Empty set (0.00 sec)

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)



mysql> delimiter //
mysql> create trigger trg_order_delete 
    -> 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)

mysql> delimiter ;
mysql> delete from orders where oid = 1;
Query OK, 1 row affected (0.00 sec)

mysql> select * from goods where gid = 'a0001';
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| A0001 | 橡皮   |  2.50 |   100 |
+-------+--------+-------+------+
1 row in set (0.00 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  orders_update_after_trigger
    -> after update  on  orders
    -> for  each row
    -> update goods set num=num+(old.onum-new.onum) where gid=old.gid;
Query OK, 0 rows affected (0.01 sec)

mysql> insert into orders(gid,name,price,onum,otime) values('A0001','橡皮',2.50,20,now());
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   2 | A0001 | 橡皮   |  2.50 |   20 | 2025-11-11 |
+-----+-------+--------+-------+------+------------+
1 row in set (0.00 sec)

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> insert into orders(gid,name,price,onum,otime) values('A0001','橡皮',2.50,20,now());
Query OK, 1 row affected, 1 warning (0.01 sec)

mysql> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   2 | A0001 | 橡皮   |  2.50 |   20 | 2025-11-11 |
|   3 | A0001 | 橡皮   |  2.50 |   20 | 2025-11-11 |
+-----+-------+--------+-------+------+------------+
2 rows in set (0.00 sec)

mysql> select * from goods;
+-------+-----------+-------+------+
| gid   | name      | price | num  |
+-------+-----------+-------+------+
| A0001 | 橡皮      |  2.50 |   60 |
| 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> delimiter //
mysql> create trigger trg_order_update 
    -> after update on orders for each row
    -> begin
    ->     update goods set num = num + old.onum where gid = old.gid;
    ->     update goods set num = num - new.onum where gid = new.gid;
    -> end //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> insert into orders (gid, name, price, onum, otime)
    -> values ('C0001', '铅笔', 1.2, 10, '2025-11-07 11:00:00');
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> update orders set onum = 5 where oid = 2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0
mysql> select * from goods where gid = 'C0001';
+-------+--------+-------+------+
| gid   | name   | price | num  |
+-------+--------+-------+------+
| C0001 | 铅笔   |  1.20 |  110 |
+-------+--------+-------+------+
1 row in set (0.01 sec)

二、存储过程

1、使用mydb7.openlab库；


mysql> use mydb7_openlab;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

mysql> select * from emp_new;
+------+--------+------+----------------+----------+-------+
| sid  | name   | age  | worktime_start | incoming | dept2 |
+------+--------+------+----------------+----------+-------+
| 1789 | 张三   |   35 | 1980-01-01     |     4000 |   101 |
| 1674 | 李四   |   32 | 1983-04-01     |     3500 |   101 |
| 1776 | 王五   |   24 | 1990-07-01     |     2000 |   101 |
| 1568 | 赵六   |   57 | 1970-10-11     |     7500 |   102 |
| 1564 | 荣七   |   64 | 1963-10-11     |     8500 |   102 |
| 1879 | 牛八   |   55 | 1971-10-20     |     7300 |   103 |
+------+--------+------+----------------+----------+-------+
6 rows in set (0.01 sec)

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 from emp_new;
    -> end //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> call s1();
+--------+----------+
| name   | incoming |
+--------+----------+
| 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 (0.00 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 in_name varchar(11),out out_age int) begin   select age into out_age from emp_new where name+in_name;end //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;

mysql> call s2('李四',@age);
Query OK, 0 rows affected, 7 warnings (0.01 sec)

mysql> select @age;
+------+
| @age |
+------+
|  32  |
+------+
1 row in set (0.00 sec)




mysql> delimiter //
mysql> create procedure s2()
    -> begin
    ->     select name, age from emp_new;
    -> end //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> call s2();
+--------+------+
| name   | age  |
+--------+------+
| 张三   |   35 |
| 李四   |   32 |
| 王五   |   24 |
| 赵六   |   57 |
| 荣七   |   64 |
| 牛八   |   55 |
+--------+------+
6 rows in set (0.00 sec)

Query OK, 0 rows affected (0.00 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 in_dept int, out avg_sal float) begin   select avg(incoming) into avg_sal from emp_new where dept2=in_dept; end//
Query OK, 0 rows affected (0.01 sec)

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

mysql> delimiter ;
mysql> select @sal;
+------+
| @sal |
+------+
| 8000 |
+------+
1 row in set (0.00 sec)