Codeigniter 4 V 4.5.1 $this->db problem

Just $db->table, without $this

PHP Code:

public function get_all_items(){
        $db      = \Config\Database::connect();
        $builder = $db->table('items');
        $query = $builder->select('*')
                 ->get();

                return $query->getResult();
    }
    

    public function fetch_single_item($item_id){
        $db      = \Config\Database::connect();
        $builder = $db->table('items');
        $query = $builder->select('*')
                ->where('item_id', $item_id)
                ->get();

              return $query->getRow();
    } 


That will work