1.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;
2.mysql> create trigger order_delete_after_trigger after
-> delete on orders for each row
-> update goods set num=num+old.onum
-> where gid=old.gid;
mysql> delete from orders where oid=1;
3.mysql> create trigger order_update_after_trigger after
-> update on orders for each row
-> update goods set num=num+(new.onum-old.onum)
-> where gid=old.gid;
mysql> insert into orders(gid,name,price,onum,otime) value('D0001','计算器',28,20,now());
mysql> update orders set onum=10 where gid='D0001';
存储过程
1.mysql> create procedure proc20()
-> begin
-> select name,incoming from emp_new;
-> end //
Query OK, 0 rows affected (0.01 sec)
@age会话变量用于接收传回的值
3.mysql> create procedure s3(in in_dept int,out avg_sal float)
-> begin
-> select avg(incoming) into avg_sal from emp_new where dept=in_dept;
-> end //
