PHP测试模拟并发下单,抢购

• 抢购、秒杀是平常很常见的场景
  并发下如何解决库存的减少超卖问题

正常是查询出对应商品的库存，看是否大于0，
然后执行生成订单等操作，但是在判断库存是否大于0处，
如果在高并发下就会有问题，导致库存量出现负数

• 简单模拟一下测试一下

• 准备建表：库存 - 商品 -订单三张表，

• 商品表bt_goods

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateBtGoodsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('bt_goods', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('goods_id')->comment('商品id');
            $table->index('goods_id');
            $table->integer('cat_id')->nullable();
            $table->string('goods_name',16)->comment('商品名称');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('bt_goods');
    }
}

订单表bt_orders

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateBtOrdersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public fun