What are the drawbacks of using Singletons for database connections in PHP applications?

Using Singletons for database connections in PHP applications can lead to tight coupling, making it difficult to swap out the database connection implementation. It also violates the single responsibility principle, as the Singleton class is responsible for both creating and managing the database connection. Additionally, Singletons can introduce global state, making it harder to test and debug the code. 

class Database {
    private static $instance;

    public static function getInstance() {
        if (!self::$instance) {
            self::$instance = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');
        }
        return self::$instance;
    }
}

// Usage
$pdo = Database::getInstance();
$stmt = $pdo->query('SELECT * FROM users');

Keywords

Singletons database connections PHP applications drawbacks design pattern

Related Questions