How to make auto installer Plugin?

I found the solution:

function rating_install(){
    //Funcion que genera la instalacion del plugin
    global $wpdb;
    $table_name = $wpdb->prefix."rating";
    $create = "CRETA TABLE ".$table_name." ( "
            . "id INT( 11 ) NOT NULL AUTO_INCREMENT PRIMARY KEY, "
            . "url TINYTEXT NOT NULL, "
            . "descripcion TINYTEXT NOT NULL ) ";    
    $wpdb->query($create);
    /*require_once(ABSPATH."wp-admin/includes/upgrade.php");
    dbDelta($create);*/
}

function rating_uninstall(){
    //Funcion que genera la desinstalacion del plugin
    global $wpdb;
    $table_name = $wpdb->prefix."rating";
    $drop = "DROP TABLE IF EXISTS ".$table_name;
    $wpdb->query($drop);
    /*require_once(ABSPATH."wp-admin/includes/upgrade.php");
    dbDelta($drop);*/
}

I wrote wrong the create sentence and ussing $wpdb->query($create) works!

Thanks for all!