baoshi-was/app/Commodity.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Commodity extends Model
{
    protected $fillable=['name','sku','owner_id'];
    protected $appends=['barcode'];

    public function barcodes()
    {
        return $this->hasMany('\App\CommodityBarcode');
    }
    public function getBarcodeAttribute(){
        return $this->barcodes()->first()['code'];
    }
    public function newBarcode($barcode){
        $commodityBarcode=CommodityBarcode::where('commodity_id',$this['id'])->where('code',$barcode)->first();
        if(!$commodityBarcode){
            $commodityBarcode=new CommodityBarcode(['commodity_id'=>$this['id'],'code'=>$barcode]);
            $commodityBarcode->save();
        }
    }
}