PHP错误未定义索引[重复]

Question

所以我有一个表格和一些 php 代码来在数据库中输入信息。但是，当我运行 php 文件时，会出现以下错误：

注意：未定义索引：第 24 行 C:\xampp\htdocs\temp\insert.php 中的第一个

注意：未定义的索引：最后在 C:\xampp\htdocs\temp\insert.php 第 25 行

注意：未定义索引：第 26 行 C:\xampp\htdocs\temp\insert.php 中的电子邮件

注意：未定义索引：第 27 行 C:\xampp\htdocs\temp\insert.php 中的消息

致命错误：未捕获的 PDOException：SQLSTATE[23000]：完整性 违反约束：1048 列“第一”不能为空 C:\xampp\htdocs\temp\insert.php:29 堆栈跟踪：#0 C:\xampp\htdocs\temp\insert.php(29): PDOStatement->execute() #1 {main} 在第 29 行的 C:\xampp\htdocs\temp\insert.php 中抛出

这是我的 html 表单：

<form action="insert.php" method="post">
    <label for="first" >Firstname:</label>
    <input type="text" name="first" id="first" />
    <label for="last" >Surname:</label>
    <input type="text" name="last" id="last" />
    <label for="email" >   Email: </label>
    <input type="text" name="email" id="email" />
    <label for="message">Message:</label>
    <textarea name="message" id="message"> Enter your question here and we will get back
    to you as soon as possible </textarea>
    <input type="Submit">
</form> 

这是我的 php：

<?php
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "test";

    try {
        $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        echo "Connected successfully <br />";
    }
    catch(PDOException $e)
    {
        echo "Connection failed: " . $e->getMessage();
    }

    $query=$conn->prepare("INSERT INTO contacts (first, last, email, message) VALUES(?,?,?,?)");
    $query->bindParam(1, $first);
    $query->bindParam(2, $last);
    $query->bindParam(3, $email);
    $query->bindParam(4, $message);

    $first=$_POST['first'];
    $last=$_POST['last'];
    $email=$_POST['email'];
    $message=$_POST['message'];

    $query->execute();

    $conn = null;

    echo 'Hi '.$_POST['first'].' ' .$_POST['last'] .' thanks for your interest.</br>';
    echo 'We will contact you at '. $_POST['email'].' soon.</br>';
?>

Answer 1

编辑：刚刚认识到您只需要检查isset :) 感谢@phil

试试这个代码：

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "test";

try {
 $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
 $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 echo "Connected successfully <br />";
 }
catch(PDOException $e)
 {
 echo "Connection failed: " . $e->getMessage();
 }



$query=$conn->prepare("INSERT INTO contacts (first, last, email, message) VALUES(?,?,?,?)");
$query->bindParam(1, $first);
$query->bindParam(2, $last);
$query->bindParam(3, $email);
$query->bindParam(4, $message);

 $first=isset($_POST['first'])?$_POST['first']:"";
$last=isset($_POST['last'])?$_POST['last']:"";
$email=isset($_POST['email'])?$_POST['email']:"";
$message=isset($_POST['message'])?$_POST['message']:"";
$query->execute();

$conn = null;

echo 'Hi '.$_POST['first'].' ' .$_POST['last'] .' thanks for your interest.</br>';
echo 'We will contact you at '. $_POST['email'].' soon.</br>';
?>