class DatabaseConnection { private static $instance = null; private $connection; private function __construct() { $dsn = 'mysql:host=localhost;dbname=mydb'; $username = 'username'; $password = 'password'; $this->connection = new PDO($dsn, $username, $password); } public static function getInstance() { if (self::$instance == null) { self::$instance = new DatabaseConnection(); } return self::$instance->connection; } }In this example, the `getInstance` method is used to obtain the single instance of the database connection. A private constructor ensures that an object of the `DatabaseConnection` class can only be created from within the class itself. The `PDO` class is used to connect to a MySQL database. Overall, implementing the DB singleton pattern can help to ensure efficient use of database resources in PHP applications. The choice of which package library to use depends on individual project requirements and preferences.