PHP form processing: form data update and modification

PHP form processing: form data update and modification

In web development, forms are an indispensable part. Users submit data to the server through forms, and the server processes and saves the data. Sometimes, users may need to update or modify submitted data. This requires us to use PHP in the background to update and modify the form data.

In this article, we will explore how to use PHP to handle updates and modifications of form data. We'll use a simple example to illustrate this process. Let's say we have a contact management system and have a table containing contact information. Users can add, update and delete contact data through forms.

1. Update contact information

First, let’s take a look at how to use PHP to update existing contact information. Before doing this, we need to create a database table to store contact information, as shown below:

CREATE TABLE contacts (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(50),
    email VARCHAR(100),
    phone VARCHAR(20)
);

Next, we create a file named update.php to handle requests to update contact information. First, we need to connect to the database and query the current information of the contact we want to update:

<?php
// 连接到数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 检查连接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

// 获取联系人的ID
$id = $_GET['id'];

// 查询联系人的当前信息
$sql = "SELECT * FROM contacts WHERE id = $id";
$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);

// 显示表单用于更新联系人信息
?>

<form method="post" action="update_process.php">
    <input type="hidden" name="id" value="<?php echo $row['id']; ?>">
    <label for="name">姓名：</label>
    <input type="text" name="name" value="<?php echo $row['name']; ?>"><br>
    <label for="email">邮箱：</label>
    <input type="email" name="email" value="<?php echo $row['email']; ?>"><br>
    <label for="phone">电话：</label>
    <input type="text" name="phone" value="<?php echo $row['phone']; ?>"><br>
    <input type="submit" value="更新">
</form>

<?php
// 关闭数据库连接
mysqli_close($conn);
?>

In the above example, we first connect to the database and then get the ID of the contact we want to update from the URL . Next, we query the database and populate the form with the results. Users can modify a contact's information and submit update requests through a form.

2. Handling update requests

Now, we need to create a file called update_process.php to handle update requests. In this file, we first connect to the database and get the updated data in the form. We then use a SQL statement to update the contact data:

<?php
// 连接到数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 检查连接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

// 获取更新数据
$id = $_POST['id'];
$name = $_POST['name'];
$email = $_POST['email'];
$phone = $_POST['phone'];

// 更新联系人信息
$sql = "UPDATE contacts SET name='$name', email='$email', phone='$phone' WHERE id=$id";

if (mysqli_query($conn, $sql)) {
    echo "联系人信息更新成功";
} else {
    echo "更新失败: " . mysqli_error($conn);
}

// 关闭数据库连接
mysqli_close($conn);
?>

In the above example, we first connect to the database and get the updated data in the form. We then use the UPDATE statement to update this data into the database. If the update is successful, a success message is displayed; if the update fails, a failure message is displayed.

Through the above two examples, we can see how to use PHP to handle update and modification operations of form data. By connecting to the database and using SQL statements to manipulate data, we can easily update and modify form data. In actual development, we can improve and extend these sample codes according to specific needs. I hope this article can help you better understand and use PHP to update and modify form data.

Summary

This article introduces how to use PHP to handle update and modification operations of form data. We illustrate this process through the example of a contact management system. By connecting to the database and using the UPDATE statement to update the data, we can easily implement the update and modification functions of form data. In actual development, we can improve and extend these sample codes according to specific needs. I hope this article can help you better use PHP to update and modify form data.

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