baoshi-was/app/MaterialBoxCommodity.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

use App\Traits\ModelLogChanging;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

class MaterialBoxCommodity extends Model
{
    use ModelLogChanging;

    protected $fillable=[
        "material_box_id","commodity_id","amount"
    ];

    public function materialBox():BelongsTo
    {
        return $this->belongsTo(MaterialBox::class);
    }
}