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MySQL练习05

news 2025/8/16 9:07:09

题目

步骤

触发器

use mydb16_trigger;    #使用数据库create table goods(
gid char(8) primary key,
name varchar(10),
price decimal(8,2),
num int);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);

添加数据

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);

输入触发器

create trigger insert_after_orders_trigger after insert
on orders for each row update goods
set num=num-new.onum where gid=new.gid;

删除触发器

create trigger delete_after_orders_trigger after
delete on orders for each row update goods
set num=num+old.onum where gid=old.gid;

更新触发器

create trigger update_after_orders_trigger
after update on orders
for each row update goods
set num=num+(old.onum-new.onum)
where gid=new.gid;

存储过程

存储过程s1

delimiter //    #切换命令分隔符
create procedure s1()
beginselect name '姓名',incoming '工资' from emp_new;
end //
delimiter ;

存储过程s2

delimiter //    #更改命令结束符
create procedure s2(in in_name varchar(11), out out_age int)
beginselect age into out_age from emp_new where name=in_name;
end //
delimiter ;

存储过程s3

delimiter //
create procedure s3(in in_dept2 int, out avg_sal double(10,2))
beginselect avg(incoming) into avg_sal from emp_new where dept2=in_dept2;
end //
delimiter ;