After establishing a PHP connection to the root directory, create a database.

Connecting to the root user in PHP can be achieved by using the mysqli or PDO extensions.

Use the mysqli extension:

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

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

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

// 创建数据库
$sql = "CREATE DATABASE myDB";
if (mysqli_query($conn, $sql)) {
    echo "数据库创建成功";
} else {
    echo "创建数据库时出错: " . mysqli_error($conn);
}

// 关闭连接
mysqli_close($conn);
?>

Use the PDO extension:

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

try {
    $conn = new PDO("mysql:host=$servername;dbname=myDB", $username, $password);
    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "连接成功";
    
    // 创建数据库
    $sql = "CREATE DATABASE myDB";
    // 使用 exec() 方法执行 SQL 语句
    $conn->exec($sql);
    echo "数据库创建成功";
} catch(PDOException $e) {
    echo "连接失败: " . $e->getMessage();
}

// 关闭连接
$conn = null;
?>

In the above example, suppose you want to create a database named "myDB". When connecting as the root user, you can omit the database name and then use the "CREATE DATABASE" command in an SQL statement to create the database.