PDO（PHP Data Object），Mysqli，以及对sql注入等问题的解决
这篇是上一篇 http://www.cnblogs.com/charlesblc/p/5987951.html 的续集。
看有的文章提到mysqli和PDO都支持多重查询，所以下面的url会造成表数据被删。
http://localhost:8080/test.php?id=3;delete%20from%20users
可是我在mysql版本的函数，上面的sql都不能执行。是不是不支持多重查询了？
这篇文章 http://www.runoob.com/php/php-mysql-connect.html 对mysqli, PDO的方式有一些介绍，不详细。
主要用的这篇文章：http://blog.csdn.net/yipiankongbai/article/details/17277477
三种连接方式：
// PDO $pdo = new PDO("mysql:host=localhost;dbname=database", 'username', 'password'); // mysqli, procedural way $mysqli = mysqli_connect('localhost','username','password','database'); // mysqli, object oriented way $mysqli = new mysqli('localhost','username','password','database');
先看mysqli过程型：
<?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $con = mysqli_connect('10.117.146.21:8306', 'root', '[password]'); mysqli_select_db($con, 'springdemo'); $input_id = trim($_GET['id']); $sql = 'select nickname from user where id = ' . $input_id; print_r('SQL is:' . $sql . '<br/>'); $result = mysqli_query($con, $sql); if ($result != null) { print_r('rows:' . mysqli_num_rows($result) . '<br/>'); while ($row = mysqli_fetch_array($result)) { print_r($row['nickname'] . '<br/>'); } } mysqli_close($con); ?>
测试：
http://localhost:8080/test.php?id=3 PHP version:5.5.30 SQL is:select nickname from user where id = 3 rows:1 micro http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 SQL is:select nickname from user where id = 3 or 1=1 rows:4 abc micro helloworld 你好
加上real_escape函数：
?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $con = mysqli_connect('10.117.146.21:8306', 'root', '[password]'); mysqli_select_db($con, 'springdemo'); $input_id = mysqli_real_escape_string($con, $_GET['id']); $sql = 'select nickname from user where id = ' . $input_id; print_r('SQL is:' . $sql . '<br/>'); $result = mysqli_query($con, $sql); if ($result != null) { print_r('rows:' . mysqli_num_rows($result) . '<br/>'); while ($row = mysqli_fetch_array($result)) { print_r($row['nickname'] . '<br/>'); } } mysqli_close($con); ?>
测试：
http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 SQL is:select nickname from user where id = 3 or 1=1 rows:4 abc micro helloworld 你好 注：仍然有问题，因为没有在url里面加引号！
采用推荐的mysqli的PreparedStatement方式：
?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $con = new mysqli('10.117.146.21:8306', 'root', '[password]', 'springdemo'); //mysqli_select_db($con, 'springdemo'); $query = $con->prepare('SELECT nickname FROM user WHERE id = ?'); $query->bind_param('s', $_GET['id']); $query->execute(); $result = $query->get_result(); if ($result != null) { print_r('rows:' . mysqli_num_rows($result) . '<br/>'); while ($row = mysqli_fetch_array($result)) { print_r($row['nickname'] . '<br/>'); } } mysqli_close($con); ?>
测试：
http://localhost:8080/test.php?id=3 PHP version:5.5.30 rows:1 micro http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 rows:1 micro
PDO与mysqli的对比：
性能
PDO和MySQLi都有非常好的性能。在非prepared statements的基准测试下，MySQLi略快2.5%，而prepared statements下是6.5%，可以说对于性能无关紧要。
| PDO | MySQLi | |
| Database support | 12 different drivers | MySQL only |
| API | OOP | OOP + procedural |
| Connection | Easy | Easy |
| Named parameters | Yes | No |
| Object mapping | Yes | Yes |
| Prepared statements (client side) |
Yes | No |
| Performance | Fast | Fast |
| Stored procedures | Yes | Yes |
PDO方式：
<?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $pdo = new PDO("mysql:host=10.117.146.21:8306;dbname=springdemo", 'root', '[password]'); class Name { public $nickname; public function info() { return '#'.$this->nickname; } } $input_id = $_GET['id']; $sql = 'select nickname from user where id = ' . $input_id; print_r('SQL is:' . $sql . '<br/>'); $result = $pdo->query($sql); $result->setFetchMode(PDO::FETCH_CLASS, 'Name'); if ($result != null) { while ($row = $result->fetch()) { print_r($row->info() . '<br/>'); } } $pdo=null; ?>
测试：
http://localhost:8080/test.php?id=3 PHP version:5.5.30 SQL is:select nickname from user where id = 3 #micro http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 SQL is:select nickname from user where id = 3 or 1=1 #abc #micro #helloworld #你好
加上转码：
$input_id = $pdo->quote($_GET['id']);
测试：
http://localhost:8080/test.php?id=3 PHP version:5.5.30 SQL is:select nickname from user where id = '3' #micro http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 SQL is:select nickname from user where id = '3 or 1=1' #micro
注意，pdo的quote自动加了引号，解决了这个问题。
http://localhost:8080/test.php?id=3%27%20or%201=%271 PHP version:5.5.30 SQL is:select nickname from user where id = '3\' or 1=\'1' #micro
并且，尝试自己加引号去做侵入也没有用的。引号被转码了，所以成功防住攻击。
PDO的prepared statement：
<?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $pdo = new PDO("mysql:host=10.117.146.21:8306;dbname=springdemo", 'root', '[password]'); $prepared = $pdo->prepare('select nickname from user where id = :id'); $prepared->execute(array(':id' => $_GET['id'])); while ($results = $prepared->fetch(PDO::FETCH_ASSOC)) { print_r($results['nickname'] . '<br/>'); } $pdo=null; ?>
实验：
http://localhost:8080/test.php?id=3 PHP version:5.5.30 micro http://localhost:8080/test.php?id=3%20or%201=1 PHP version:5.5.30 micro
都不再出现sql注入的威胁。
PDO里面多次用到fetch：
| 值 | 说明 |
|---|---|
| PDO::FETCH_ASSOC | 关联数组形式。 |
| PDO::FETCH_NUM | 数字索引数组形式。 |
| PDO::FETCH_BOTH | 两者数组形式都有，这是默认的。 |
| PDO::FETCH_OBJ | 按照对象的形式，类似于以前的mysql_fetch_object()函数。 |
| PDO::FETCH_BOUND | 以布尔值的形式返回结果，同时将获取的列值赋给bindParam()方法中指定的变量。 |
| PDO::FETCH_LAZY | 以关联数组、数字索引数组和对象3种形式返回结果。 |
把上面程序给prepared statement传参数的过程改了一下：
<?php header('Content-Type: text/html; charset=utf-8'); echo "PHP version:" . PHP_VERSION . "<br/>"; $pdo = new PDO("mysql:host=10.117.146.21:8306;dbname=springdemo", 'root', '[password]'); $prepared = $pdo->prepare('select nickname from user where id = :id'); $prepared->bindParam(':id', $_GET['id']); $prepared->execute(); while ($results = $prepared->fetch(PDO::FETCH_ASSOC)) { print_r($results['nickname'] . '<br/>'); } $pdo=null; ?>
实验之后，结果对于上面哪些url，都能得到正确的结果。
性能方面：
PDO和MySQLi都有非常好的性能。在非prepared statements的基准测试下，MySQLi略快2.5%，而prepared statements下是6.5%，可以说对于性能无关紧要。
如果你真的非常介意这一点点性能的话，而自带的MySQL扩展比两者都快，你可以考虑下它。
上面部分来自这篇：http://blog.csdn.net/yipiankongbai/article/details/17277477 《PDO vs. MySQLi 选择哪一个？》
