每次都会添加一条额外的 Sql 条记录

Question

我正在开发一个聊天网络应用程序。问题是每当加载页面时，每次都会将一条空消息插入数据库。

代码如下

          <!--   Insert MySQL datbase into HTML     -->
<?php
$connection = mysqli_connect("localhost", "root", "", "tru");
$query = "SELECT * FROM shouts ORDER BY id Desc LIMIT 8";
$shouts = mysqli_query($connection, $query);
?>



                  <!--   Insert MySQL datbase into HTML     -->
     <?php while ($row = mysqli_fetch_assoc($shouts)) : ?>
      <li> <?php echo $row['shout']; ?> <b>&nbspSent at&nbsp</b><?php echo $row['Time']; ?></li>
          <?php endwhile; ?>

    </ul>
  </div>
  <footer>
      <form action="index.php" method="post">
      <label>Shout Text: </label>
      <input type="text" name="shout" placeholder="Enter your message here">
      <input type="submit" id="submit" value="SHOUT!" >
    </form>
      <?php 
                  <!--   Insert  into MySQL datbase     -->

$link = mysqli_connect("localhost", "root", "", "tru");
$sql = "INSERT INTO shouts (name,shout) VALUES ('$_POST[name]','$_POST[shout]')";
if(mysqli_query($link, $sql)){
echo "Records added successfully.";
} else
{
  echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}

// close connection
mysqli_close($link);
?>   
</footer>
</div>
</body>
</html>

Answer 1

<?php 

if(isset($_POST["name"])){
    $link = mysqli_connect("localhost", "root", "", "tru");
    $sql = "INSERT INTO shouts (name,shout) VALUES ('$_POST[name]','$_POST[shout]')";
    if(mysqli_query($link, $sql)){
        echo "Records added successfully.";
    } 
    else
    {
        echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
    }

    // close connection
    mysqli_close($link);
}

用一个 if 语句就解决了。如果设置了 POST 名称变量，它只会添加一条记录。

Answer 2

你无条件insert连续，所以这是意料之中的。那么，应该具备怎样的条件呢？当然，在页面加载时您不想 insert 大喊大叫，只希望在 POST 上大喊大叫。所以你需要测试请求是否是 post:

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // insert the row
}

但即使是POST，也需要测试是否有效，所以查名字喊：

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if ((isset($_POST["name"])) && (isset($_POST["shout"])) && ($_POST["name"]) && ($_POST["shout"])) {
        //insert the row
    }
}

不过要注意 SQL injection。

每次都会添加一条额外的 Sql 条记录

An extra Sql record is being added everytime

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