Weird error when using MySQL when using PDO - php

Question

I encountered a very strange bug today. I am getting sideblinded by this so bad as it's breaking my entire application.
So, I have this little framework that I've built where I have a standard modell, so snippeting this will be a little long and descriptive.
<?php include('inc/inc.php'); ?>
<?php
if(!empty($_POST['answer']) && !empty($_POST['levelstart'])){
if($stmt = $site->answerQuestion($_POST['levelstart'], $_POST['answer'])){
if($stmt[0]){
echo json_encode(array('success' => true, 'correct' => $stmt[1], 'correctanswer' => $stmt[2], 'round_end' => $stmt[3]));
}else{
echo json_encode(array('success' => false, 'error' => 'error occurred'.$stmt[1]));
}
}else{
echo json_encode(array('sucess' => false, 'error' => 'Unknown error'));
}
}else{
echo json_encode(array('success' => false, 'error' => 'Provide all necessary parameters.'));
}
?>
this piece of code outputs the following.
INSERT INTO quiz_level_starts (`user_id`, `question_id`, `time`, `round_id`, `type`, `success`, `ref_id`) VALUES ('4', '10', '1471887809', '', '1', '1', '905'){"success":false,"error":"error occurred23000"}
The generated query above is only a dummy one that i simple put together so I don't need the parameterization for simply testing. The "error" key in the json array contains error data, and the errorcode is dumped there.
23000 is the mysql error code for there being a duplicate unique column, but there is no unique column that I'm using in the query(see table struct below.)
Since the function answerQuestion is a very long one, I'll only paste the related lines next. In $site->answerQuestion it calls a function called "insertLevelStarts" which is supposed to insert an entry to the db.
This is how i call it:
if($stmtss = $this->db->insertLevelStarts($_SESSION['user']['id'], $stmts['return'][0]['id'], time(), $roundid, 1, 1, $levelstart)){
And this is how it's declared, also the rest of the related and unknown code:
public function insertLevelStarts($user_id, $question_id, $time, $round_id, $type = 0, $success = 0, $refid = 0){
/*
Type=0 start 1 stop
success=0 for start 1 if successfull on stop
*/
$query = 'INSERT INTO quiz_level_starts (`user_id`, `question_id`, `time`, `round_id`, `type`, `success`, `ref_id`) VALUES (:user_id, :question_id, :time, :round_id, :type, :success, :refid)';
echo $this->genFakeQuery($query, array(
':user_id' => $user_id,
':question_id' => $question_id,
':time' => $time,
':type' => $type,
':success' => $success,
':refid' => $refid,
':round_id' => $round_id
));
return $this->execInsert($query, array(
':user_id' => $user_id,
':question_id' => $question_id,
':time' => $time,
':type' => $type,
':success' => $success,
':refid' => $refid,
':round_id' => $round_id
)
);
}
public function genFakeQuery($query, $array){
foreach($array as $key => $val){
$query = str_replace($key, "'$val'", $query);
}
return $query;
}
public function execUpdate($query, $preparray, $updatearr){
try {
$stmt = $this->db->prepare($query);
$stmt->execute(array_merge($preparray, $updatearr));
$rows = $stmt->rowCount();
if($rows > 0){
return array('type' => 'rowsaffected', 'return' => $rows);
}else{
return array('type' => 'noreturn', 'return' => 'none');
}
} catch(PDOException $ex) {
return array('type' => 'error', 'return' => $ex);
}
}
public function updateClause($query, $update, $updatearr){
if(count($update) > 0){
$count = 0;
foreach($update as $k => $v){
if($count > 0){
$query .= ',';
}
$query .= " `$k` = :$k";
$updatearr[":$k"] = $v;
$count++;
}
}
return array('query' => $query, 'updatearr' => $updatearr);
}
The aforementioned query
INSERT INTO quiz_level_starts (`user_id`, `question_id`, `time`, `round_id`, `type`, `success`, `ref_id`) VALUES ('4', '10', '1471887809', '', '1', '1', '905')
inserts into a table looking like this:
CREATE TABLE IF NOT EXISTS `quiz_level_starts` (
`id` int(11) NOT NULL,
`user_id` int(11) NOT NULL,
`question_id` int(11) NOT NULL,
`time` int(11) NOT NULL,
`type` int(11) NOT NULL,
`success` int(11) NOT NULL,
`ref_id` int(11) NOT NULL,
`round_id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `quiz_level_starts`
ADD PRIMARY KEY (`id`);
ALTER TABLE `quiz_level_starts`
MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;
Will greatly appriciate any help recieved.

Answer 1

I assume that the error occurs because round_id is an integer field that can not be NULL and has no default value and you pass it an empty value.
Try if this query works:
INSERT INTO quiz_level_starts (`user_id`, `question_id`, `time`, `round_id`, `type`, `success`, `ref_id`) VALUES ('4', '10', '1471887809', '0', '1', '1', '905')