SpiceManagementSystem/app/Models/SpiceSupplier.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class SpiceSupplier extends Model
{
    use HasFactory;

    protected $table = 'spices_suppliers'; // explizit, weil der Standard sonst 'spice_suppliers' wäre

    protected $fillable = [
        'spice_id',
        'supplier_id',
        'amount',
        'supplied_at',
    ];

    public function spice()
    {
        return $this->belongsTo(Spice::class);
    }

    public function supplier()
    {
        return $this->belongsTo(Supplier::class);
    }

    protected static function booted(): void
    {
        static::created(function (SpiceSupplier $ss) {
            SpiceStockMovement::create([
                'spice_id'    => $ss->spice_id,
                'amount'      => $ss->amount,
                'source_type' => 'delivery',
                'source_id'   => $ss->id,
                'description' => 'Lieferung' . ($ss->supplier ? ' von ' . $ss->supplier->name : ''),
            ]);
            $ss->spice->recalculateQuantity();
        });

        static::deleted(function (SpiceSupplier $ss) {
            SpiceStockMovement::where('source_type', 'delivery')
                ->where('source_id', $ss->id)
                ->delete();
            $ss->spice->recalculateQuantity();
        });
    }
}