screen/application/common/model/GoodsInstall.php

<?php

namespace app\common\model;

use think\Model;


class GoodsInstall extends Model
{
    protected $type=[
        'fee'=>'json',
    ];
    protected $autoWriteTimestamp=true;

    public function link(){
        return $this->hasMany(GoodsInstallLink::class);
    }

    public function getFee($num){
        foreach ($this['fee'] as $fee){
            if($num>=$fee['num_min'] && $num<$fee['num_max']){
                return bcmul($fee['amount'],$num);
            }
       }
        return 0;
    }






























    public static function init()
    {
        self::afterDelete(function (self $goodsInstall){
            $goodsInstall->link()->delete();
        });
    }
}