class DB{

public $hostname,$database,$username,$password;

public function __construct(){
    $this->hostname = "";
    $this->database = "";
    $this->username = "";
    $this->password = "";
    $this->errors = array();
}

private function connessione(){
    mysql_connect($this->hostname,$this->username,$this->password) or $this->errors[] = mysql_error();
    mysql_select_db($this->database) or $this->errors[] = mysql_error();
    $this->PrintErrors();
}

public function query($query){
    $this->query = $query;
    $this->result = mysql_query($this->query) or $this->errors[] = mysql_error();
    if($this->result){
        return $this->result;
    }else{
        $this->PrintErrors();
    }
}

public function PrintErrors(){
    foreach(array_unique($this->errors) as $key=>$value){
        if(!empty($value)){
            echo "Errore : ".$value."<br/>";
        }
    }
}
}