php - undefined index PHP 放置在主机上

Question

我必须为学校建立一个网站。它需要与数据库链接。在 localhost 上一切正常并且正常工作，但是当我尝试将其上传到学校主机上时，出现此错误:

Notice: Undefined index: vragen in /mnt/studentenhomes/arnaud.gandibleux/public_html/datamanagement/index.php on line 44

我找不到解决方案

index.php

<div id="tekst">
            <table align='center'>
                <?php
                //if (isset($_GET['vragen'])){

                if ($_GET['vragen'] === 'Alleclubs') {
                    getclubs();

                } elseif ($_GET['vragen'] === 'ledenvjf') {
                    getVJFleden();
                    echo "test";
                } elseif ($_GET['vragen'] === 'ledenffbj') {
                    getFFBJleden();
                }

                elseif (isset($_GET['clubnr'])) {
                    getLedenPerClubEnID($_GET['clubnr']);
                }
                else{
                    getclubs();
                }
                // }
                ?>
            </table>

Crud.php

        function getVJFleden() {
        global $mysqli;

        $result = $mysqli->query("SELECT * FROM Leden l JOIN Clubs c ON l.clubnr = c.clubnr join Bonden b
    ON b.ID_bond = c.ID_bond LEFT JOIN adressen a ON a.ID_adress = l.ID_adress WHERE b.naam_bond = 'VJF';");
        if ($result) {
            if ($result->num_rows > 0) {
                echo"<caption>Alle leden VJF</caption>";
                echo "<th>Voornaam</th><th>achternaam</th><th>leeftijd</th><th>Kye</th><th>adress</th>";
                while ($leden = $result->fetch_object()) {
                    echo "<tr><td>$leden->lid_voornaam</td> ";
                    echo "<td>" . $leden->lid_achternaam . "</td> ";
                    echo "<td>" . $leden->lid_leeftijd . "</td> ";
                    echo "<td>" . $leden->kye . "</td> ";
                    echo "<td>" . $leden->straatnaam . " " . $leden->huisnummer . " " . $leden->postcode . " " . $leden->gemeente . "</td> ";
                    echo "<td><form id='update' action='update.php' method='POST'>
                       <input type='hidden' name='id' value='" . $leden->ID_lid . "'/>
                       <input type='hidden' name='clubnr' value='" . $_GET['clubnr'] . "'/>
                       <input type='image' src='update.png' alt='Update' width='22' height='22'>
                       </form>
                       <form id='delete' action='deleteLid.php' method='POST'>
                       <input type='hidden' name='id' value='" . $leden->ID_lid . "'/>
                       <input type='image' src='delete.png' alt='detele' width='22' height='22'>
                       </form></td> ";
                }
            }
        }
        $mysqli->close();
    }

    function getFFBJleden() {
        global $mysqli;
        #, Adressen a
        #AND l.ID_adress = a.ID_adress
        $result = $mysqli->query("SELECT * FROM Leden l JOIN Clubs c ON l.clubnr = c.clubnr join Bonden b ON b.ID_bond = c.ID_bond LEFT JOIN adressen a ON a.ID_adress = l.ID_adress WHERE b.naam_bond = 'FFBJ';");
        if ($result) {
            if ($result->num_rows > 0) {
                echo"<caption>Alle leden VJF</caption>";
                echo "<th>Voornaam</th><th>achternaam</th><th>leeftijd</th><th>Kye</th><th>adress</th>";
                while ($leden = $result->fetch_object()) {

                    echo "<tr><td>$leden->lid_voornaam</td> ";
                    echo "<td>" . $leden->lid_achternaam . "</td> ";
                    echo "<td>" . $leden->lid_leeftijd . "</td> ";
                    echo "<td>" . $leden->kye . "</td> ";
                    echo "<td>" . $leden->straatnaam . " " . $leden->huisnummer . " " . $leden->postcode . " " . $leden->gemeente . "</td> ";
                    echo "<td><form id='update' action='update.php' method='POST'>
                       <input type='hidden' name='id' value='" . $leden->ID_lid . "'/>
                       <input type='hidden' name='clubnr' value='" . $_GET['clubnr'] . "'/>
                       <input type='image' src='update.png' alt='Update' width='22' height='22'>
                       </form>
                       <form id='delete' action='deleteLid.php' method='POST'>
                       <input type='hidden' name='id' value='" . $leden->ID_lid . "'/>
                       <input type='image' src='delete.png' alt='detele' width='22' height='22'>
                       </form></td> ";
                }
            }
        }
        $mysqli->close();
    }

Answer 1

在尝试使用数组索引之前，您需要确保它存在。由于它是一个 $_GET 变量，因此可能没有作为 URL 参数传递。

取消注释

//if (isset($_GET['vragen'])){

至

if (isset($_GET['vragen'])){