<?php

class Database {

    private static $database;
    private static $pdo;

    private function __construct(){
        $dbname = "DATABASE";
        $host = "127.0.0.1";
        $username = "USERNAME";
        $password = "PASSWORD";

        Database::$database = $this;
        $dsn = "mysql:dbname=$dbname;host=$host";
        try {
            Database::$pdo = new PDO($dsn, $username, $password);
        } catch (PDOException $e){
            echo $e->getMessage();
        }
    }

    public static function getInstance(){
        if(!isset(Database::$database)){
            Database::$database = new Database();
        }
        return Database::$pdo;
    }
}

?