Multiple Choice Quiz - not updating responses - php

Question

I have a form that outputs:
Quiz_Assign_ID (Combines User_ID with Quiz ID)
Question ID
Checkboxes for inputting the response (Option A, Option B, Option C)
<div class="Main">
<form method="post" action="LP_Quiz_Student_Quiz_Responses.php">
<?php
$quiz_id = trim($_GET['quiz_id']);
$quiz_assign_id = trim($_GET['quiz_assign_id']);
$i = 1;
$count=1;
$sel_query=("SELECT Quiz.quiz_id, Quiz.quiz_title, Quiz_Questions.quiz_id, Quiz_Questions.quiz_question_id, Quiz_Questions.question, Quiz_Questions.option1, Quiz_Questions.option2, Quiz_Questions.option3, Quiz_Questions.answer FROM Quiz, Quiz_Questions WHERE (Quiz.quiz_id=Quiz_Questions.quiz_id) and (Quiz.quiz_id=?)");
$stmt = $conn->prepare($sel_query);
$stmt->bind_param("i", $quiz_id);
$stmt->execute();
$result = $stmt->get_result(); // get the mysqli result
if($result->num_rows === 0) exit('No Quiz Questions!');
while($row = $result->fetch_assoc()) { ?>
<p></p>
<p> </p>
<table>
<tr>
<td>
</td>
<td>
<input name="quiz_assign_id" type="hidden" value=" <?php echo $quiz_assign_id; ?>" /> <input name="quiz_question_id" type="hidden" value=" <?php echo $row["quiz_question_id"]; ?>" /></td>
<td> </td>
</tr>
<tr>
<td>
<h4>Question <?php echo $i++; ?> </h4>
</td>
<td>
<h4><?php echo $row["question"]; ?> </h4>
</td>
<td> </td>
</tr>
<tr>
<td>
<h4>A</h4>
</td>
<td><?php echo $row["option1"]; ?> </td>
<td>
<input name="Response[<?php echo $quiz_question_id; ?>]" type="checkbox" value="Option A" style="width: 20px" /></td>
</tr>
<tr>
<td>
<h4>B</h4>
</td>
<td><?php echo $row["option2"]; ?> </td>
<td>
<input name="Response[<?php echo $quiz_question_id; ?>]" type="checkbox" value="Option B" /></td>
</tr>
<tr>
<td>
<h4>C</h4>
</td>
<td><?php echo $row["option3"]; ?> </td>
<td>
<input name="Response[<?php echo $quiz_question_id; ?>]" type="checkbox" value="Option C" /></td>
</tr>
</table>
<?php
}
?>
<input name="Submit1" type="submit" value="submit" />
</form>
</div>
Upon submission I run the following script, which captures the response but does not get the question_id and Quiz_Assign_ID and does not update the values in the database:
<?php
if(!empty($_POST['Response'])) {
foreach ($_POST['Response'] as $value) {
$quiz_assign_id=trim($_POST['quiz_assign_id']);
$quiz_question_id=$_POST['quiz_question_id'];
echo 'Answer'; echo $value;
echo 'Question:'; echo $quiz_question_id;
echo 'Student ID'; echo $quiz_assign_id; echo 'successfully assigned! <br>';
$stmt = $conn -> prepare('UPDATE Quiz_Assign_Student_Question SET response = ? WHERE quiz_assign_id = ? and quiz_question_id =? ');
if (
$stmt &&
$stmt -> bind_param('sss', $value, $quiz_assign_id, $quiz_question_id) &&
$stmt -> execute() &&
$stmt -> affected_rows === 1
) {
echo "<script>
alert('Responses submitted!');
window.history.go(-2);
</script>";
} else {
echo"<script>
window.history.go(-2);
</script>";
}
}
}
?>
I have been playing with it for hours, but with no luck.

Answer 1

Because you are using check boxes en not radio buttons, you should change your input checkbox name attribute, so it's sending a nested array with the question ID as a key and the answers array as the value, like so: (notice the extra []) Also $quiz_question_id is not defined, you should use the $row array.
<input name="Response[<?php echo $row['quiz_question_id']; ?>][]" type="checkbox" value="Option A" style="width: 20px" /></td>
Because the response array is now nested, the question answers are grouped by question_id. To iterate over the nested response array, use the following for loop:
foreach ($_POST['Response'] as $question_id => $answered) {
echo "Question ID:".$question_id."<br />";
// iterate answers
foreach ($answered as $answer) {
echo "Answered: ".$answer."<br />";
}
// Or transform to comma separated string
echo "Answered: ".implode(", ", $answered)."<br />";
}
So your LP_Quiz_Student_Quiz_Responses.php could look like this:
if(!empty($_POST['Response'])) {
$done = 0;
foreach ($_POST['Response'] as $quiz_question_id => $values) {
$quiz_assign_id = trim($_POST['quiz_assign_id']);
echo 'Answers'; print_r($values); // Values is an array here.
echo 'Question:'; echo $quiz_question_id;
echo 'Student ID'; echo $quiz_assign_id; echo 'successfully assigned! <br>';
// Because $values is an array, transform it into a comma separated string to insert them into the database
// But you could also make a database table with answers and loop over the $values array.
$value = implode(', ', $values);
$stmt = $conn->prepare('UPDATE Quiz_Assign_Student_Question SET response = ? WHERE quiz_assign_id = ? and quiz_question_id =? ');
$stmt->bind_param('sss', $value, $quiz_assign_id, $quiz_question_id);
$stmt->execute();
if ($stmt->affected_rows > 0) {
$done++;
}
}
echo "<script>";
if ($done) {
echo "alert('Responses submitted!');";
}
echo "window.history.go(-2);";
echo "</script>";
}
To accommodate both type of questions with check boxes and questions with radio buttons, you can use the same response code, but first check if its an array before transforming it into a string.
Questions with radio buttons, one answer per question possible:
<input name="Response[<?php echo $row['quiz_question_id']; ?>]" type="radio" value="Option A" style="width: 20px" /></td>
Questions with check boxes, multiple answers per question possible:
<input name="Response[<?php echo $row['quiz_question_id']; ?>][]" type="checkbox" value="Option A" style="width: 20px" /></td>
And now your LP_Quiz_Student_Quiz_Responses.php could look like this:
if(!empty($_POST['Response'])) {
$done = 0;
foreach ($_POST['Response'] as $quiz_question_id => $values) {
$quiz_assign_id = trim($_POST['quiz_assign_id']);
// If it's an array (checkbox), transform to string.
// Else it is already a string (radio).
if (is_array($values)) {
$values = implode(', ', $values);
}
$stmt = $conn->prepare('UPDATE Quiz_Assign_Student_Question SET response = ? WHERE quiz_assign_id = ? and quiz_question_id =? ');
$stmt->bind_param('sss', $values, $quiz_assign_id, $quiz_question_id);
$stmt->execute();
if ($stmt->affected_rows > 0) {
$done++;
}
}
echo "<script>";
if ($done) {
echo "alert('".$done." Responses submitted!');";
}
echo "window.history.go(-2);";
echo "</script>";
}
But with above code you can accommodate all kind of field types.
To put it simple:
foreach ($_POST['Response'] as $question_id => $answered) {
echo "Question ID:".$question_id."<br />";
// Check if array, it's a checkbox or multiple select question
if (is_array($answered)) {
// iterate answers
foreach ($answered as $answer) {
echo "Answered: ".$answer."<br />";
}
// Or transform to comma separated string
echo "Answered: ".implode(", ", $answered)."<br />";
} else {
// radio, hidden, input, select or textarea question
echo "Answered: ".$answered."<br />";
}
}
I hope this points you in the right direction.