Wordpress plugin with classes, namespaces and psr-0 autoloading

I'm pretty new at this Wordpress thingy and I've now made my own theme and would like to create a plugin that handles my slideshow.

(I have to teach this for some pupils later on, so I cannot just use an existing plugin)

I have implemented the autoloader from http://www.php-fig.org/psr/psr-0 at the bottom and it works fine.

I can call all the methods in my class and everything, so thats fine. Here's the actual question:

When the

register_activation_hook(__FILE__, array('vendor\Keystroke\KeystrokeSlider', 'install')); 

is called, then it runs the method

class KeystrokeSlider{ const VERSION = '1.0.0'; static public function install(){ global $wpdb; $charset_collate = $wpdb->get_charset_collate(); $tableName = $wpdb->prefix . 'ks_albums'; $sql = "CREATE TABLE IF NOT EXISTS $tableName ( id INT(11) NOT NULL AUTO_INCREMENT, name VARCHAR(255) NULL, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP NULL, PRIMARY KEY (id) ) $charset_collate;"; self::upgrade(); dbDelta($sql); add_option('keystroke_slider_version', self::VERSION); } } 

but the dbDelta() is an undefined function. I could see that it was trying to set the namespace in front of the function (I don't know why, since it's not at class method, but a function, right?). Anyway I've tried calling it like this

\dbDelta() 

That seems to be working, but It still can't find the function. Can I manually require the dbDelta in the class or is there something else wrong?

Sorry for the very long question...

Ulrik McArdle