View file app/Models/Board.php

<?php

declare(strict_types=1);

namespace App\Models;

use App\Traits\UploadTrait;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;

/**
 * Class Board
 *
 * @property int id
 * @property int sort
 * @property int parent_id
 * @property string name
 * @property int count_items
 * @property int closed
 * @property Collection children
 * @property Board parent
 */
class Board extends BaseModel
{
    use UploadTrait;

    /**
     * Indicates if the model should be timestamped.
     *
     * @var bool
     */
    public $timestamps = false;

    /**
     * The attributes that aren't mass assignable.
     *
     * @var array
     */
    protected $guarded = [];

    /**
     * Директория загрузки файлов
     *
     * @var string
     */
    public $uploadPath = UPLOADS . '/boards';

    /**
     * Возвращает связь родительской категории
     *
     * @return BelongsTo
     */
    public function parent(): BelongsTo
    {
        return $this->belongsTo(self::class, 'parent_id')->withDefault();
    }

    /**
     * Возвращает связь подкатегорий
     *
     * @return HasMany
     */
    public function children(): HasMany
    {
        return $this->hasMany(self::class, 'parent_id')->orderBy('sort');
    }
}