    public static function remove($id)
    {
        global $DB;
        global $website;

        if(empty($id))
            return 'invalid_id';

        $DB->execute('
            DELETE FROM nv_notes
                WHERE website = '.protect($website->id).'
                  AND id = '.protect($id).'
                LIMIT 1'
        );

        return 'true';
    }

The software constructs all or part of an SQL command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended SQL command when it is sent to a downstream component.