PHP While loop of ID's only works with first id

Question

I am currently building a lightweight blogging platform with some nice Material Design but i have run into a problem. I have a table with ID's and I want to change the value of public in my table so that you can hide articles from the blog, to do so I made a loop but it only works on the first id and none of the other id's. Here is my code:

        try {
        if (isset($_POST['submit'])) {
            $stmt = $db->query('SELECT postID FROM blog_posts ORDER BY postID DESC');

            while ($row = $stmt->fetch()) {
                // set public based on the submitted value from your form
                $public = empty($_POST['public'][$row['postID']]) ? 0 : 1;

                // do the update
                $stmt = $db->prepare('UPDATE blog_posts SET public = ? WHERE postID = ?');
                $stmt->execute(array($public, $row['postID']));
                header('Location: index.php');
            }
        }
    } catch (PDOException $e) {
        echo $e->getMessage();
    }

If it is of any use here is my full page of PHP, also my fully loaded page can be found here

Thanks in advance.

Answer 1

Please put this header('Location: index.php'); outside the while-loop and don't override the $stmt instead use another one :

//.......
//.......
while ($row = $stmt->fetch()) {

    // set public based on the submitted value from your form    
    $public = empty($_POST['public'][$row['postID']]) ? 0 : 1;

    // do the update  
    //Create another statement
    $stmt2 = $db->prepare('UPDATE blog_posts SET public = ? WHERE postID = ?');
    $stmt2->execute(array(
        $public,
        $row['postID']
    ));
}

header('Location: index.php');
//.......
//.......