MySQL 代码的 MySQLi 等效项

使用 MySQL 数据库是开发 Web 应用程序的常见需求之一。在 PHP 中，我们可以使用 MySQLi 扩展来与 MySQL 数据库进行交互。MySQLi 是 MySQL 扩展库的增强版，提供了更多功能和更好的性能。本文将介绍 MySQL 代码的 MySQLi 等效项，并提供一些示例代码。

php
$host = "localhost";
$username = "root";
$password = "password";
$dbname = "mydatabase";
$conn = new mysqli($host, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
echo "成功连接到数据库！";

php
$sql = "SELECT * FROM users";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"] . ", Name: " . $row["name"] . ", Email: " . $row["email"] . "
";
    }
} else {
    echo "没有找到任何结果。";
}

php
$name = "John Doe";
$email = "john@example.com";
$sql = "INSERT INTO users (name, email) VALUES ('$name', '$email')";
if ($conn->query($sql) === true) {
    echo "数据插入成功！";
} else {
    echo "插入数据时出错：" . $conn->error;
}

php
$id = 1;
$name = "Jane Doe";
$sql = "UPDATE users SET name='$name' WHERE id=$id";
if ($conn->query($sql) === true) {
    echo "数据更新成功！";
} else {
    echo "更新数据时出错：" . $conn->error;
}

php
$id = 1;
$sql = "DELETE FROM users WHERE id=$id";
if ($conn->query($sql) === true) {
    echo "数据删除成功！";
} else {
    echo "删除数据时出错：" . $conn->error;
}

php
$conn->close();