public function vote($uid, $args)
{
XDB::execute('INSERT INTO survey_votes
- SET survey_id = {?}, uid = {?};', $this->id, $uid); // notes the user as having voted
+ SET survey_id = {?}, uid = {?}',
+ $this->id, ($uid == 0) ? null : $uid); // notes the user as having voted
$vid = XDB::insertId();
for ($i = 0; $i < count($this->questions); $i++) {
$ans = $this->questions[$i]->checkAnswer($args[$i]);