laravel怎么为模型属性添加readonly特性_laravel模型属性readonly特性设置方法

class Post extends Model
{
    protected $fillable = ['title', 'content', 'user_id'];

    public function setUser_idAttribute($value)
    {
        if ($this->exists && $this->user_id !== null) {
            // 已存在模型且已有 user_id，则不更新
            return;
        }

        $this->attributes['user_id'] = $value;
    }
}

class Post extends Model
{
    protected $fillable = ['title', 'content', 'user_id'];

    protected static function boot()
    {
        parent::boot();

        static::updating(function ($model) {
            $original = $model->getOriginal('user_id');
            if ($model->isDirty('user_id') && $original !== null) {
                $model->user_id = $original; // 还原原始值
            }
        });
    }
}

Post::create([
    'title' => 'Hello',
    'content' => 'World',
    'user_id' => 123  // 只在创建时设置
]);

$post->update(['title' => 'New Title']); // 不传 user_id

class User extends Model
{
    public function getFullNameAttribute()
    {
        return $this->first_name . ' ' . $this->last_name;
    }
}