PHP开发中如何实现数据的持久化存储和读取

// 连接到数据库
$conn = mysqli_connect('localhost', 'username', 'password', 'dbname');

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

// 插入数据
$sql = "INSERT INTO users (name, age, email) VALUES ('John Doe', 25, 'johndoe@example.com')";
if (mysqli_query($conn, $sql)) {
    echo "数据插入成功";
} else {
    echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

// 读取数据
$sql = "SELECT * FROM users";
$result = mysqli_query($conn, $sql);

if (mysqli_num_rows($result) > 0) {
    // 输出每一行数据
    while($row = mysqli_fetch_assoc($result)) {
        echo "姓名: " . $row["name"]. " 年龄: " . $row["age"]. " 邮箱: " . $row["email"]. "<br>";
    }
} else {
    echo "0 结果";
}

// 关闭数据库连接
mysqli_close($conn);

// 写入数据
$file = fopen("data.txt", "w");

fwrite($file, "John Doe,25,johndoe@example.com
");
fwrite($file, "Jane Smith,30,janesmith@example.com
");

fclose($file);

// 读取数据
$file = fopen("data.txt", "r");

while(!feof($file)){
    $line = fgets($file);
    $data = explode(",", $line);

    echo "姓名: " . $data[0] . " 年龄: " . $data[1] . " 邮箱: " . $data[2] . "<br>";
}

fclose($file);