数据库-触发器，存储过程

按照题目要求完成下列题目：

1.触发器

mysql> use mydb16_trigger;
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 (0.01 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> 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 (0.01 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)
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 (0.00 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)

//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
mysql> create trigger orders_insert_after_trigger
    -> after insert on orders for each row
    -> update goods set num=num-new.onum where gid=new.gid;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into orders values(oid,'A0001','橡皮',2.5,20,now());
Query OK, 1 row affected, 1 warning (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> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   2 | A0001 | 橡皮   |  2.50 |   20 | 2024-07-25 |
+-----+-------+--------+-------+------+------------+
1 row in set (0.00 sec)

//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 oid=1;
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)

//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 (0.00 sec)

mysql> insert into orders values(oid,'C0001','铅笔',1.20,30,now());
Query OK, 1 row affected, 1 warning (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 |   90 |
| D0001 | 计算器    | 28.00 |   20 |
+-------+-----------+-------+------+
4 rows in set (0.00 sec)

mysql> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   3 | C0001 | 铅笔   |  1.20 |   30 | 2024-07-25 |
+-----+-------+--------+-------+------+------------+
1 row in set (0.00 sec)

mysql> update orders set onum=50 where oid=3;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from orders;
+-----+-------+--------+-------+------+------------+
| oid | gid   | name   | price | onum | otime      |
+-----+-------+--------+-------+------+------------+
|   3 | C0001 | 铅笔   |  1.20 |   50 | 2024-07-25 |
+-----+-------+--------+-------+------+------------+
1 row in 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 |   70 |
| D0001 | 计算器    | 28.00 |   20 |
+-------+-----------+-------+------+
4 rows in set (0.00 sec)

2.存储过程

mysql> use mydb7_openlab
Database changed
mysql> show tables;
+-------------------------+
| Tables_in_mydb7_openlab |
+-------------------------+
| dept                    |
| emp                     |
| emp_new                 |
| user                    |
+-------------------------+
4 rows in set (0.00 sec)


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 (0.00 sec)
//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)

//创建存储过程s2，实现输入员工姓名后返回员工的年龄
mysql> desc emp_new;
+----------------+-------------+------+-----+---------+-------+
| Field          | Type        | Null | Key | Default | Extra |
+----------------+-------------+------+-----+---------+-------+
| sid            | int         | YES  |     | NULL    |       |
| name           | varchar(11) | YES  |     | NULL    |       |
| age            | int         | YES  |     | NULL    |       |
| worktime_start | date        | YES  |     | NULL    |       |
| incoming       | int         | YES  |     | NULL    |       |
| dept2          | int         | YES  |     | NULL    |       |
+----------------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)
mysql> delimiter //
mysql> create procedure s2(in s2_name varchar(11),out s2_age int)
    -> begin
    ->       select age into s2_age from emp_new where name=s2_name;
    -> end //
Query OK, 0 rows affected (0.00 sec)
mysql> delimiter ;
mysql> call  s2('张三',@s2_age);
Query OK, 1 row affected (0.00 sec)

mysql> select @s2_age;
+---------+
| @s2_age |
+---------+
|      35 |
+---------+
1 row in set (0.00 sec)

//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> 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 (0.00 sec)

mysql> delimiter //
mysql> create procedure s3(in s3_dept2 int ,out s3_avgincoming int)
    -> begin
    ->     select avg(incoming) into s3_avgincoming from emp_new where dept2=s3_dept2;
    -> end //
Query OK, 0 rows affected (0.01 sec)

mysql> delimiter ;
mysql> call s3(101,@s3_avgincoming);
Query OK, 1 row affected (0.00 sec)

mysql> select @s3_avgincoming;
+-----------------+
| @s3_avgincoming |
+-----------------+
|            3167 |
+-----------------+
1 row in set (0.00 sec)

mysql> call s3(102,@s3_avgincoming);
Query OK, 1 row affected (0.00 sec)

mysql> select @s3_avgincoming;
+-----------------+
| @s3_avgincoming |
+-----------------+
|            8000 |
+-----------------+
1 row in set (0.00 sec)