checkbox could not uncheck php - php

Question

I have written a code to save the check values of checkboxes to database.
check condition is working fine as in the checked values are saving to database when submit and it keeps checked when submit and refresh.
But when it uncheck and submit then refresh the page the checkbox still keeps remained checked. It won't saved the status of unchecked.
I include a chunk code which is related to this issue. If anyone can get the issue that'd be great.
echo "<form action='' class='' method='post'><tr>";
$sql_stamp = "SELECT check_list FROM time_stamps WHERE nJobNumber=".$nJobNumber;
$query_stamp = $conn->prepare($sql_stamp);
$query_stamp->execute();
$numRows = $query_stamp->rowCount();
if($numRows > 0){
$row_stamp = $query_stamp->fetch(PDO::FETCH_ASSOC);
$checkboxes = explode(',',$row_stamp['check_list']);
echo ' <td><center> <input type="checkbox" name="check_list[]" value="shop_drawing" '.(in_array( "shop_drawing",$checkboxes) ? "checked=checked" : "").'></td>';
echo ' <td><center><input type="checkbox" name="check_list[]" value="site_measure" '.(in_array( "site_measure",$checkboxes) ? "checked=checked" : "").'></td>';
echo ' <td><center><input type="checkbox" name="check_list[]" value="shop_drawings_approved" '.(in_array( "shop_drawings_approved",$checkboxes) ? "checked =checked" : "").'></td>';
echo '<td><center> <input type="checkbox" name="check_list[]" id="check" value="batch" '.(in_array( "batch",$checkboxes) ? "checked=checked" : "").'></td>';
echo '<td><center> <input type="text" name="batch_no"><br> </td>';
echo ' <td><center> <input type="submit" name="submit" value="Submit"/> </td>';
echo '<td><input type="hidden" name="job_number[result]" value="'."true".'"</td>';
echo '<td><input type="hidden" name="job_number[number]" value="'.$nJobNumber.'"</td>';
}else{
echo '<td><center><input type="checkbox" name="check_list[]" id="check" value="shop_drawing"></td>';
echo '<td><center><input type="checkbox" name="check_list[]" id="check" value="site_measure"></td>';
echo '<td><center><input type="checkbox" name="check_list[]" id="check" value="shop_drawings_approved"> </td>';
echo '<td><center> <input type="checkbox" name="check_list[]" id="check" value="batch"></td>';
echo '<td><center> <input type="text" name="batch_no"><br> </td>';
echo "<td><center> <input type='submit' name='submit' value='submit'></td>";
echo '<td><input type="hidden" name="job_number[result]" value="'."false".'"</td>';
echo '<td><input type="hidden" name="job_number[number]" value="'.$nJobNumber.'"</td>';
}
echo "</tr> </form>";
}
echo "</tbody> </table>";
?>
Insert values to database:
if(isset($_POST['submit']))
{
$checkbox = $_POST["check_list"];
$job_number = $_POST["job_number"];
$batch_no = $_POST["batch_no"];
date_default_timezone_set('Australia');
$date_time = date("Y-m-d h:i:sa");
//$username = "$SESSION[userid]";
if($job_number["result"] == "true"){
if(!empty($_POST['check_list']))
{
$checkboxes = implode(",",$_POST['check_list']);
$stmt = $link->prepare('UPDATE time_stamps SET time_date=?,username=?, batch_no=?,check_list=? WHERE nJobNumber=?');
$stmt->bind_param('ssssi',$date_time,$username,$batch_no,$checkboxes,$job_number["number"]);
$stmt->execute();
}
}
else{
if(!empty($_POST['check_list']))
{
$checkboxes = implode(",",$_POST['check_list']);
$stmt = $link->prepare('INSERT INTO time_stamps (nJobNumber,time_date,username,batch_no,check_list) VALUES (?,?,?,?,?)');
$stmt->bind_param('issss',$job_number["number"],$date_time,$username,$batch_no,$checkboxes);
$stmt->execute();
}
}
}
Basically, What's my requirement is when a user uncheck a 'checked' checkbox it should be unchecked when submit the form (after a refresh). But in my case it keeps checked.

Answer 1

Neither of your queries will execute if the user submits a form with no checkboxes checked. While this may be ok for your INSERT query, it will not allow the check_list field to be updated. So you will need to change the code for updates from this:
if(!empty($_POST['check_list'])) {
$checkboxes = implode(",",$_POST['check_list']);
$stmt = $link->prepare('UPDATE time_stamps SET time_date=?,username=?, batch_no=?,check_list=? WHERE nJobNumber=?');
$stmt->bind_param('ssssi',$date_time,$username,$batch_no,$checkboxes,$job_number["number"]);
$stmt->execute();
}
to this:
$checkboxes = empty($_POST['check_list']) ? '' : implode(",",$_POST['check_list']);
$stmt = $link->prepare('UPDATE time_stamps SET time_date=?,username=?, batch_no=?,check_list=? WHERE nJobNumber=?');
$stmt->bind_param('ssssi',$date_time,$username,$batch_no,$checkboxes,$job_number["number"]);
$stmt->execute();
You may also want to change the insert code in the same way if you want to insert a record even when the user doesn't check any checkboxes.
Thanks to #Phil for his input.

Answer 2

I think I see a couple of problems. I see this line:
$job_number = $_POST["job_number"];
But then I see you use this:
if($job_number["result"] == "true"){
So I ask, is $job_number an array or just a string/value?
Also, unchecked checkboxes don't submit a value. And since you test for a not empty $_POST['check_list'] value your UPDATE will never run. Remove the ! character.