Illuminate\Database\Eloquent\Builder::whereKey PHP 메소드

    public function whereKey($id)
    {
        if (is_array($id)) {
            $this->query->whereIn($this->model->getQualifiedKeyName(), $id);
            return $this;
        }
        return $this->where($this->model->getQualifiedKeyName(), '=', $id);
    }