1、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> create trigger orders_after_insert_trigger after insert on orders for each row-> update goods set numnum-new.onum-> where gidnew.g…
package day01;
public class IntegerDemo { public static void main(String[] args) { // int 占用 4字节 int a 300; // int b -2147483648; // int c 2147483647; // int d 2147483648; 编译错误,超过了当前变量类型可容纳…