我的while和我的数组sqli请求有问题

I'm php starter and i wan't to make my project. Here is my problem: i make a script which update info on my sqli server but a strange problem comes. It doesn't want to update for no reason.

My code:

<?php

                    $itemchoice = array(
                        'value' => array( '', "1" => $item1, "2" => $item2, "3" => $item3, "4" => $item4, "5" => $item5),
                        'name' => array('', "1" => "item1name", "2" => "item2name", "3" => "item3name", "4" => "item4name", "5" => "item5name"),
                    );

                    $nombre_actuel = 1;

                    echo '<form method="post">';
                    while ($nombre_actuel <= $nombredeligne)
                    {
                        echo '<input type="text" name="'.$itemchoice['name'][$nombre_actuel].'" value="'.$itemchoice['value'][$nombre_actuel].'">';
                        $nombre_actuel++;
                    }
                    echo '<input type="submit" name="envoyer" value="Envoyer">';
                    echo '</form>';

                    if (isset($_POST['item1name'])) {
                        $newitem1 = $_POST['item1name'];
                        $newitem1sql = 'UPDATE navbar SET valeur='.$newitem1.' WHERE item="item1" ';
                        $newitem1result = mysqli_query($db1, $newitem1sql);
                    }

The line

 $newitem1sql = 'UPDATE navbar SET valeur='.$newitem1.' WHERE item="item1" ';

Doesn't work for any reason

Change this line:

$newitem1sql = 'UPDATE navbar SET valeur='.$newitem1.' WHERE item="item1" ';

to this:

$newitem1sql = 'UPDATE navbar SET valeur="'.$newitem1.'" WHERE item="item1" ';

Note: You are open to SQL Injection attack. You should not just take the $_Post[] input and shove it in your SQL without sanitizing. Sanitize and parameterize your query.