How to modify database information in php

With the development of Internet technology, website functions are becoming more and more complex, and database operations are becoming more and more frequent. In order to ensure the stability and security of website operation, database information often needs to be modified. This article will introduce how to use PHP to modify database information.

1. Connect to the database

Before using PHP to operate the database, you first need to connect to the database. To connect to the database, you need to use MySQLi or PDO extension. Here, MySQLi is used as an example. The specific code is as follows:

$servername = "localhost"; //服务器名
$username = "root"; //数据库用户名
$password = "password"; //数据库密码
$dbname = "myDB"; //数据库名

// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检测连接是否成功
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

2. Modify database information

1. Modify the data table

To modify the field name, type, length, etc. in the data table information, you can use the ALTER TABLE statement. The sample code is as follows:

$sql = "ALTER TABLE users MODIFY COLUMN password VARCHAR(50) NOT NULL";
if (mysqli_query($conn, $sql)) {
    echo "数据表 users 修改成功";
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

2. Modify the data in the data table

To modify the data in the data table, you can use the UPDATE statement. The sample code is as follows:

$sql = "UPDATE users SET password='newpassword' WHERE id=1";

if (mysqli_query($conn, $sql)) {
    echo "数据表 users 修改成功";
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

3. Modify the data in the database

To modify the data in the database, you can use the UPDATE statement. The sample code is as follows:

$sql = "UPDATE myDB.users SET password='newpassword' WHERE id=1";

if (mysqli_query($conn, $sql)) {
    echo "数据库 myDB 中 users 表数据修改成功";
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

3. Close the connection

After completing the modification of the database information, you need to close the database connection in time to release resources. The sample code is as follows:

mysqli_close($conn);

Summary

This article introduces how to use PHP to modify database information, including connecting to the database, modifying the data table, modifying the data in the data table and modifying the data in the database. aspects. Of course, in actual development, more complex operations need to be performed based on specific needs. We hope that through the introduction of this article, readers will be able to operate the database more skillfully and improve the stability and security of the website.

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