thinkphp6使用mysql悲观锁解决商品超卖问题的实现

CREATE TABLE `goods` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(100) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  `status` tinyint(1) NOT NULL DEFAULT '1',
  `total` int(11) NOT NULL DEFAULT '0',
  `sell` int(11) NOT NULL DEFAULT '100',
  `price` decimal(10,2) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
 
INSERT INTO `test`.`goods`(`id`, `name`, `status`, `total`, `sell`, `price`) VALUES (1, '商品', 1, 0, 100, 15.00);

CREATE TABLE `orders` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `uid` int(11) NOT NULL DEFAULT '0',
  `create_time` datetime NOT NULL,
  `status` tinyint(1) NOT NULL DEFAULT '1',
  `goods_id` int(11) NOT NULL DEFAULT '0',
  `order_no` varchar(200) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

<?php
 
namespace app\controller;
 
use app\BaseController;
use think\facade\Db;
 
class Test extends BaseController
{
 
    /**
     * 不加锁
     * @return string|void
     */
    public function test_1()
    {
        $num = 1;
        $goods_id = 1;
        Db::startTrans();
        try {
            $where = [];
            $where['id'] = $goods_id;
            $where['status'] = 1;
            $goods_info = Db::table('goods')->where($where)->find();
            if (empty($goods_info)) {
                return '商品不存在';
            }
            $total = $goods_info['total'];
            $sell = $goods_info['sell'];
            if ($total < $num) {
                return '库存不足';
            }
            $data['total'] = $total-$num;
            $data['sell'] = $sell+$num;
            $res = Db::table('goods')->where(['id'=>$goods_id])->update($data);
            $order_data = [];
            $order_data['uid'] = rand(1000,9999);
            $order_data['status'] = 1;
            $order_data['create_time'] = date('Y-m-d H:i:s');
            $order_data['goods_id'] = $goods_id;
            $order_data['order_no'] = date('YmdHis').rand(1000,10000);
            $order_res = Db::table('orders')->insert($order_data);
            Db::commit();
        } catch (\Exception $e) {
            // 回滚事务
            Db::rollback();
            echo $e->getMessage();
            exit('rollback');
        }
        echo '请求成功';
    }
 
    /**
     * 加锁--悲观锁
     * @return string|void
     */
    public function test_2()
    {
        $num = 1;
        $goods_id = 1;
        Db::startTrans();
        try {
            $where = [];
            $where['id'] = $goods_id;
            $where['status'] = 1;
            $goods_info = Db::table('goods')->lock(true)->where($where)->find();
            if (empty($goods_info)) {
                return '商品不存在';
            }
            $total = $goods_info['total'];
            $sell = $goods_info['sell'];
            if ($total < $num) {
                return '库存不足';
            }
            $data['total'] = $total-$num;
            $data['sell'] = $sell+$num;
            $res = Db::table('goods')->where(['id'=>$goods_id])->update($data);
            $order_data = [];
            $order_data['uid'] = rand(1000,9999);
            $order_data['status'] = 1;
            $order_data['goods_id'] = $goods_id;
            $order_data['order_no'] = date('YmdHis').rand(1000,10000);
            $order_data['create_time'] = date('Y-m-d H:i:s');
            $order_res = Db::table('orders')->insert($order_data);
            Db::commit();
        } catch (\Exception $e) {
            // 回滚事务
            Db::rollback();
            echo $e->getMessage();
            exit('rollback');
 
        }
        echo '请求成功';
    }
 
}