PHP class not found with namespaces - php

Question

I'm new to using namespaces. In this example I made class, which handles database connection and I'm trying to use it inside the other classes. Can you explain what is wrong?
Connection.php
namespace Database;
class Connection
{
private static $instance = null;
private $pdo;
private function __construct()
{
$this->pdo = new PDO("mysql:host=localhost;dbname=database;", "root", "pw");
}
public static function get()
{
if (is_null(self::$instance))
self::$instance = new Connection();
return self::$instance;
}
}
Auth.php
namespace PHPAuth;
use Database\Connection;
class Auth
{
protected $dbh;
public function __construct()
{
$this->dbh = Connection::get();
...
Thanks in advance.
Edit: Ok, now I included autoloader and including class is now working correctly. But now I'm getting error when using $dbh in Auth like $query = $this->dbh->query("SELECT * FROM...");
Fatal error: Call to undefined method Database\Connection::query()
in...

Answer 1

First issue with class not found
I'll add the answer (which worked for you) for the first issue for reference: "Namespaces doesn't automatically load the files. You need to add an autoloader for that."
Second issue with undefined method
Fatal error: Call to undefined method Database\Connection::query()
The answer is in the error message. You've made the class Database\Connection into a singleton where Database\Connection::get() returns an instance of itself (which doesn't have any ->query() method), and not the actual PDO instance.
If you want that method to return the PDO instance instead, I would do something like this:
namespace Database;
use PDO;
class Connection
{
private static $pdo;
private function __construct()
{
// Leave the constructor private so it still becomes
// a singleton and so we can't instantiate this class.
}
public static function get()
{
if (is_null(self::$pdo)) {
self::$pdo = new PDO("mysql:host=localhost;dbname=database;", "root", "pw");
}
return self::$pdo;
}
}
Now the Connection class have become a Factory for the PDO-connection.
Connection::get() will return the same PDO instance over and over and you should be able to call $this->dbh->query("...") from your Auth class.