对比分析PDO和Mysqli

php操作mysql数据库，大家都知道有三种驱动，mysql mysqli pdo，其中mysql在php7之后被废除了。不是本文重点。咱现在来分析一下mysqli和PDO的区别，下面一张表用来说明他们的区别

连接方式

// PDO
$pdo = new PDO("mysql:host=localhost;dbname=database", 'username', 'password');

// mysqli面向过程
$mysqli = mysqli_connect('localhost','username','password','database');

// mysqli面向对象
$mysqli = new mysqli('localhost','username','password','database');

对数据库的支持方面

pdo多种支持

代码表现

var_dump(PDO::getAvailableDrivers());

参数绑定

POD方式

$params = array(':username' => 'test', ':email' => $mail, ':last_login' => time() - 3600);

$pdo->prepare('
    SELECT * FROM users
    WHERE username = :username
    AND email = :email
    AND last_login > :last_login');

$pdo->execute($params);

mysqli方式

$query = $mysqli->prepare('
    SELECT * FROM users
    WHERE username = ?
    AND email = ?
    AND last_login > ?');

$query->bind_param('sss', 'test', $mail, time() - 3600);
$query->execute();

对象映射

假设我们有一个类，是如下这样

class User {
    public $id;
    public $first_name;
    public $last_name;

    public function info()
    {
        return '#'.$this->id.': '.$this->first_name.' '.$this->last_name;
    }
}

再看看两者的方式

$query = "SELECT id, first_name, last_name FROM users";

// PDO
$result = $pdo->query($query);
$result->setFetchMode(PDO::FETCH_CLASS, 'User');

while ($user = $result->fetch()) {
    echo $user->info()."\n";
}
// MySQLI, procedural way
if ($result = mysqli_query($mysqli, $query)) {
    while ($user = mysqli_fetch_object($result, 'User')) {
        echo $user->info()."\n";
    }
}
// MySQLi, object oriented way
if ($result = $mysqli->query($query)) {
    while ($user = $result->fetch_object('User')) {
        echo $user->info()."\n";
    }
}

安全方面

二者都可以防止sql注入

代码

// PDO, "manual" escaping
$username = PDO::quote($_GET['username']);

$pdo->query("SELECT * FROM users WHERE username = $username");

// mysqli, "manual" escaping
$username = mysqli_real_escape_string($_GET['username']);

$mysqli->query("SELECT * FROM users WHERE username = '$username'");

预处理机制

// PDO, prepared statement
$pdo->prepare('SELECT * FROM users WHERE username = :username');
$pdo->execute(array(':username' => $_GET['username']));

// mysqli, prepared statements
$query = $mysqli->prepare('SELECT * FROM users WHERE username = ?');
$query->bind_param('s', $_GET['username']);
$query->execute();

总结

pdo的强大之处是显而易见的，支持多种数据库，还有参数绑定是特色，所以还是要会用PDO哦