<?php
    ///
    //print_r($_SESSION);
    if ($_POST) {
        $tmp = array();
        $tmp["nom"] = $_POST["nom"];
        $tmp["disquedur"] = $_POST["disquedur"];
        $tmp["commentaire"] = $_POST["commentaire"];
        $tmp["date"] = date("d-m-Y H:i:s");
 
        //print_r($tmp);
        //$_SESSION['tab'][] = $tmp;
        try {
            $sqli = new mysqli("localhost", "rootpma", "9fz3Cn4KAC", "TestStock");
            $sqli->query("insert into gestion (nom) values ('','$nom')");
            $sqli = $tmp;
        } catch (mysqli_sql_exception $e) {
            echo "MySQLi Error Code: " . $e->getCode() . "<br />";
            echo "Exception Msg: " . $e->getMessage();
            exit; // exit and close connection.
        }
    }
    ?>
    <h2>Formulaire</h2>
    <form method="post" action=""> 
        nom :
        <input type="text" name="nom" value="<?php echo $nom; ?>"/>
        <br><br>
        disque dur:
        <select name="disquedur" size="1">
            <optgroup label="Kingston"></optgroup>
            <option>Kingston UV400:<br>
            50026B777C01C578:<br>
            120go
            <optgroup label="Samsung"></optgroup>
            <option>Samsung 860EVO:<br>
            8806088936017:<br>
            500go
            <optgroup label="Western Digital"></optgroup>
            <option>Western Digital WD500LPCX:<br><br>
            WX71AA73VDVKM:<br>
            500go
            <option>Western Digital WD10EUCX:<br>
            WCC0S0968794T:<br>
            1000go
            <option>Western Digital WD20EZRX:<br>
            WCC300975857T:<br>
            2000go
            <optgroup label="Crucial"></optgroup>
            <option>Crucial BX500:<br>
            1919E181CF6B:<br>
            240go
            <option>Crucial MX500:<br>
            1918E1FF9936:<br>
            500go
        </select>
        <br><br>
        Commentaire:<br>
        <textarea name="commentaire" rows="5" cols="40"><?php echo $commentaire; ?></textarea>
        <br><br>
        <input type="submit"  value="Submit"> 
    </form>
    <h2>Recapitulatif:</h2>

<table>
           <thead>
               <tr>
                   <td>Nom</td>
                   <td>Date</td>
                   <td>disque dur</td>
                   <td>Commentaire</td>
               </tr>
           </thead>
           <tbody>
               <?php foreach ($tmp['sqli'] as $element): ?>
                   <tr>
                       <td><?php echo $element['nom']; ?></td>
                       <td><?php echo $element['date']; ?></td>
                       <td><?php echo $element['disquedur']; ?></td>
                       <td><?php echo $element['commentaire']; ?></td>
                   </tr>
               <?php endforeach; ?>
           </tbody>
       </table>

Plutôt que

Code : Tout sélectionner

<?php echo $nom; ?>

tu peux

Code : Tout sélectionner

<?= $nom; ?>

Pour l'insertion il suffit de réutiliser tes variables affecter https://www.w3schools.com/php/php_mysql ... ements.asp

 $sqli->query("INSERT INTO gestion (nom) values ($nom)");