abstract class Model
{
  private $_data = [];
  public function __construct($data)
  {
    $this->_data = $data;
  }

  public function __get($var) { return $this->_data[$var]; }

  protected static $pk = 'id';
  protected static $table = null;
  protected static $connection; // PDO Connection

  public function find($pk)
  {
    $q = self::$connection->prepare('SELECT * FROM :table WHERE :column = :value');
    $res = $q->execute([':table' => static::$table, ':column' => static::$pk, ':value' => $pk]);
    $objects = []
    foreach ($res as $ob) {
      $objects[] = new self($ob);
    }
    return $objects;
  }
}





class User extends Model
{
  protected static $table = 'users';
}
$users = User::find(1);
echo $users[0]->login // возвращает поле логин