Caramel-CRM/app/Models/LineItem.php

<?php

namespace App\Models;

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

class LineItem extends Model
{
    use HasFactory;

    protected $fillable = [
        'invoice_id',
        'position',
        'is_section',
        'title',
        'description',
        'unit_id',
        'quantity',
        'price',
    ];

    public function invoice()
    {
        return $this->belongsTo(Invoice::class);
    }

    public function unit()
    {
        return $this->belongsTo(Unit::class);
    }
}