class User { private $pdo; public function __construct() { $this->pdo = new PDO('mysql:host=localhost;dbname=mydb', 'username', 'password'); } public function registerUser($username, $email, $password) { $stmt = $this->pdo->prepare('INSERT INTO users (username, email, password) VALUES (?, ?, ?)'); $hashed_password = password_hash($password, PASSWORD_DEFAULT); $stmt->execute([$username, $email, $hashed_password]); return $this->pdo->lastInsertId(); } public function updateUser($id, $username, $email, $password) { $stmt = $this->pdo->prepare('UPDATE users SET username = ?, email = ?, password = ? WHERE id = ?'); $hashed_password = password_hash($password, PASSWORD_DEFAULT); $stmt->execute([$username, $email, $hashed_password, $id]); return $stmt->rowCount(); } public function getUsers() { $stmt = $this->pdo->query('SELECT * FROM users'); return $stmt->fetchAll(); } }This code uses PHP's PDO library to interact with a MySQL database. The User model has methods to register a new user, update their profile, and retrieve a list of all users. The package library for working with PHP Model might include popular PHP frameworks like Laravel, Symfony, or CodeIgniter, which provide built-in support for the Model-View-Controller pattern and include pre-built models for common tasks like authentication and database interaction.