Привет всем! Я с ООП дело имею впервые.. а вопрос вот в чем, в общем я написал код, и в нем получилось очень много лишних подключений к БД. Вот примерно то что получилось.

<?php
header('Content-Type: text/html; charset=UTF-8;');
class Configuration{
	
	const DB_HOST = 'localhost';
	const DB_USER = 'root';
	const DB_PASS = '';
	const DB_NAME = 'test';
	
	private $sql = Array();
	private $res = Array();
	private $arr = Array();
	private $cnt = Array(); // count
	private $cls = Array(); // css
	private $obj = Array();
	private $id  = Array();
	private $out;
	private $con;
	
	public function __construct(){
		if(!isset($_GET['category']))
			$_GET['category'] = null;
		if(!isset($_GET['element']))  
			$_GET['element'] = null;
		if(!isset($_GET['details'])) 
			$_GET['details'] = null;
	}
	
	final protected function database_connect(){
		$this -> con = new mysqli(self::DB_HOST, self::DB_USER, self::DB_PASS, self::DB_NAME);
		if(!$this -> con)
			return false;
		$this -> con -> query("/*!40101 SET NAMES 'UTF8' */");
		return $this -> con;
	}
	
	public function show_data($d){
		return $d;
	}
}
error_reporting(E_ALL);
$obj_Configuration 	= new Configuration();

// requires
require_once $path.'/inc/classes/class.Root.php';
require_once $path.'/inc/classes/class.Validation.php';
require_once $path.'/inc/classes/class.Menu.php';
require_once $path.'/inc/classes/class.Content.php';


$obj_Validation = new Validation();
$obj_Menu = new Menu($obj_Validation, $_GET['category'], $_GET['element']);
$obj_Content = new Content($obj_Validation, $_GET['category'], $_GET['element'], $_GET['details']);

$menu = $obj_Configuration -> show_data($obj_Menu -> build_menu());
// $content = $obj_Content -> show_content();
?>

<?php
class Menu extends Configuration{
	
	public function __construct($obj, $category_id, $element_id){
		$this -> obj['Validation'] = $obj;
		$this -> id['category'] = $this ->  obj['Validation'] -> only_digits($category_id);
		$this -> id['element']  = $this ->  obj['Validation'] -> only_digits($element_id);
	}
	
	private function get_count_element_rows($element_id, $category_id){
		$this -> sql['count_element_rows'] = "
		SELECT `id`
		FROM `kvartira`
		WHERE `category_element_id`='".$element_id."'
		AND `category_id`=".$category_id."
		";
		$this -> res['count_element_rows'] = $this -> database_connect() -> query($this -> sql['count_element_rows']);
		if(!$this -> res['count_element_rows']) return '?';
		$this -> cnt['count_element_rows'] = $this -> res['count_element_rows'] -> num_rows;
		return $this -> cnt['count_element_rows'];
	}
	
	public function build_menu(){
		$this -> sql['categories'] = "
		SELECT `id`, `title` 
		FROM `categories` 
		WHERE `hide`='0'
		ORDER BY `order`
		ASC
		";
		$this -> res['categories'] = $this -> database_connect() -> query($this -> sql['categories']);
		if(!$this -> res['categories']) return false;
		while($this -> arr['categories'] = $this -> res['categories'] -> fetch_array()){
			$this -> cls = $this -> obj['Validation'] -> identical_values($this -> arr['categories']['id'], $this -> id['category'], true);
			$this -> out .= '<li class="'.$this -> cls.' category"><a href="index.php?category='.$this -> arr['categories']['id'].'">'.$this -> arr['categories']['title'].'</a></li>';
			$this -> sql['category_elements'] = "
			SELECT *
			FROM `category_elements`
			WHERE `hide`='0'
			AND `category_id`='".$this -> arr['categories']['id']."'
			ORDER BY `order`
			ASC
			";
			$this -> res['category_elements'] = $this -> database_connect() -> query($this -> sql['category_elements']);
			if(!$this -> res['category_elements']) return false;
			if($this -> id['category'] != $this -> arr['categories']['id'])
				continue;
			while($this -> arr['category_elements'] = $this -> res['category_elements'] -> fetch_array()){
				$this -> cls = $this -> obj['Validation'] -> identical_values($this -> arr['category_elements']['id'], $this -> id['element'], true);
				$this -> out .= '<li class="'.$this -> cls.' element"><a href="index.php?category='.$this -> arr['categories']['id'].'&element='.$this -> arr['category_elements']['id'].'">'.$this -> arr['category_elements']['title'].' ('.$this -> get_count_element_rows($this -> arr['category_elements']['id'], $this -> arr['category_elements']['category_id']).')</a></li>';
			}
		}
		return $this -> out;
	}
}
?> 

Можно ли как то обойтись без лишних подключений к БД? То есть не использовать каждый раз функцию database_connect() из родительского класса Configuration в запросах класса Menu?