在第二个实例上调用时，Oops连接失败

I have the following , relatively simple connection script to a database :

The below script is just creating a generic interface :

<?php
//Filename: IConnectInfo.php
interface IConnectInfo
{
    const HOST ="localhost";
    const UNAME ="root";
    const PW ="";
    const DBNAME = "login";

    public static function doConnect();
}

?>

The script below, that makes use of the above interface:

<?php
//FILENAME :: UniversalConnect.php
ini_set("display_errors","1");
ERROR_REPORTING( E_ALL | E_STRICT );
include_once('IConnectInfo.php');

class UniversalConnect implements IConnectInfo
{
    private static $server=IConnectInfo::HOST;
    private static $currentDB= IConnectInfo::DBNAME;
    private static $user= IConnectInfo::UNAME;
    private static $pass= IConnectInfo::PW;
    private static $hookup;


    public static function doConnect()
    {
        self::$hookup=mysqli_connect(self::$server, self::$user, self::$pass, self::$currentDB);
        if(self::$hookup)
        {
            echo "Successful connection to MySQL:<br/>";
        }
        elseif (mysqli_connect_error(self::$hookup)) 
        {
            echo('Here is why it failed: '  . mysqli_connect_error());
        }
        return self::$hookup;
    }

}

?>

Now till here everything is neat and clean and works fine :

I tested the above two files are working , by adding the following 2 lines at the end of the above file .

$instance = new UniversalConnect();
$instance::doConnect(); 

I get a message "Successful connection to MySQL:" , perfect !!!

now comes the 3rd file : (I have commented out some of the code to make things simple) :

<?php
//FILENAME DataEntry.php
require_once('tablework/UniversalConnect.php');

class DataEntry
{
    //Variable for MySql connection
    private $hookup;
    private $sql;
    private $tableMaster;

    //Field Variables
    private $name;
    private $email;
    private $lang;

    public function __construct()
    {
        //Get table name and make connection
        $this->tableMaster="basics";


        if($this->hookup=UniversalConnect::doConnect()){
            echo "<b>connected</b>";
        }else{
            echo "<b>Not connected</b>";
        }


    }


}

$instance = new DataEntry();


?>

Now when i run the above file , somehow the connection to the database fails ! even though in UniversalConnect.php the connection is successful !

The error i get is

Here is why it failed: php_network_getaddresses: getaddrinfo failed: No such host is known. Not connected.

I really don't understand why when the connection is made in UniversalConnect.php and the same connection is being returned to dataEntry.php , does the connection Fail ! .

EDIT :: List of errors :

Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\Login2.0\tablework\UniversalConnect.php on line 19

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\Login2.0\tablework\UniversalConnect.php on line 19 Here is why it failed: php_network_getaddresses: getaddrinfo failed: No such host is known. Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\Login2.0\tablework\UniversalConnect.php on line 19

Warning: mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:\xampp\htdocs\Login2.0\tablework\UniversalConnect.php on line 19 Here is why it failed: php_network_getaddresses: getaddrinfo failed: No such host is known. Not connected.

I would appreciate any help .

Thank you .
Tenali .