class Database { private static $instance = null; private $connection; private function __construct() { $this->connection = mysqli_connect("localhost", "username", "password", "database"); } public static function getInstance() { if (self::$instance == null) { self::$instance = new Database(); } return self::$instance; } public function getConnection() { return $this->connection; } } // elsewhere in the application, retrieve the database connection using getInstance() $db = Database::getInstance()->getConnection();This code defines a "Database" class that includes a static variable that holds a single instance of the database connection. The getInstance method checks whether an instance already exists, and if not, creates a new one. The getConnection method is used to retrieve the database connection from the instance. The package library for this code is likely to be either "mysqli" or "pdo", two commonly used PHP database libraries.