使用PDO操作數據庫的好處

PDO一是PHP數據對象（PHP Data Object）的縮寫。

並不能使用PDO擴展本身執行任何數據庫操作，必須使用一個database-specific PDO driver（針對特定數據庫的PDO驅動）訪問數據庫服務器。
PDO並不提供數據庫抽象，它並不會重寫SQL或提供數據庫本身缺失的功能，如果你需要這種功能，你需要使用一個更加成熟的抽象層。
PDO需要PHP5核心OO特性的支持，所以它無法運行於之前的PHP版本。
http://baike.baidu.com/view/1278977.htm

 

PDO有非常多的操作卻是MySQL擴展庫所不具備的：

1:PDO真正的以底層實現的統一接口數庫操作接口，不管后端使用的是何種數據庫，如果代碼封裝好了以后，應用層調用基本上差不多的，當后端數據庫更換了以后，應用層代碼基本不用修改.

2:PDO支持更高級的DB特性操作，如：存儲過程的調度等,mysql原生庫是不支持的.

3:PDO是PHP官方的PECL庫，兼容性穩定性必然要高於MySQL Extension,可以直接使用 pecl upgrade pdo 命令升級.

4:PDO可以防止SQL注入，確保數據庫更加安全
PDO 防止SQL注入的原理
http://www.myhack58.com/Article/60/61/2015/63168.htm

 

預處理語句
使用語句預處理將幫助你免於SQL注入攻擊。

一條預處理語句是一條預編譯的 SQL 語句，它可以使用多次，每次只需將數據傳至服務器。其額外優勢在於可以對使用占位符的數據進行安全處理，防止SQL注入攻擊。
http://www.php100.com/html/itnews/PHPxinwen/2013/0618/13555.html

 

5.根據PHP官方計划，PHP6正式到來之時，數據庫鏈接方式統一為PDO。但是總有一小撮頑固分子，趁PHP官方還沒正式統一時，還用老式的MYSQL驅動鏈接數據庫。即使現在有部分程序改用Mysqli/pdo，只要沒用到預編譯，均和老式的Mysql驅動沒多大區別。在此，我就不點評國內的PHP生態環境了。
回歸主題，為什么說PHP必須要用PDO？除了官方要求之外，我認為作為PHP程序員，只要你目前是做開發的話，那么請選擇用PDO的程序/框架！PDO除了安全和萬金油式數據庫鏈接，還有一點是我目前覺得非常好用的！下面我就用我最近的切身體會來說。
業務環境：公司某老架構，數據庫設計的人員太菜了，設計過程完全沒有按照數據庫范式進行。各種表中使用大量的序列化形式保存（補充：json同理）。
出現問題：銷售的客服反饋，網站某用戶在編輯地址時，Mysql報錯了。
問題猜想：不用說了。肯定是引號，反斜杠引起序列化入庫不正常。
http://zhidao.baidu.com/question/1541430860923158627

 

6.安裝配置及測試
在windows下進行有關pdo測試的時候，php.ini中的extension_dir的值要填為pdo*.dll的路徑，否則無法運行pdo的相關程序。
; Directory in which the loadable extensions (modules) reside.
extension_dir = "E:\www\php5\ext"

<?php
$host = 'localhost';
$user = 'root';
$password = 'develop';
$dbname = '99game';

$dbh = new PDO("mysql:host=$host;dbname=$dbname", $user, $password); 

//=======================================================
//例子 1. Execute a prepared statement with named placeholders
/* Execute a prepared statement by binding PHP variables */
$user_id = 1;
$email = '[e-mail]';
$sth = $dbh->prepare('SELECT user_id,email,token FROM 99game_user 
    WHERE user_id = :user_id AND email = :email');
$sth->bindParam(':user_id', $user_id, PDO::PARAM_INT);
$sth->bindParam(':email', $email, PDO::PARAM_STR, 30);
$sth->execute();  
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("<br />\n");

//例子 2. Execute a prepared statement with question mark placeholders
/* Execute a prepared statement by binding PHP variables */
$user_id = 2;
$email = '[e-mail]';
$sth = $dbh->prepare('SELECT user_id,email,token FROM 99game_user 
    WHERE user_id = ? AND email = ?');
$sth->bindParam(1, $user_id, PDO::PARAM_INT);
$sth->bindParam(2, $email, PDO::PARAM_STR, 30);
$sth->execute();
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("<br />\n");

print "<hr />\n";
 //=======================================================

//=======================================================
$sth = $dbh->prepare("SELECT user_id,email,token FROM 99game_user limit 10");
$sth->execute();

/* 運用 PDOStatement::fetch 風格 */
print("PDO::FETCH_ASSOC: ");
print("Return next row as an array indexed by column name<br />\n");
$result = $sth->fetch(PDO::FETCH_ASSOC);
print_r($result);
print("<br />\n");
print("\n");

print("PDO::FETCH_BOTH: ");
print("Return next row as an array indexed by both column name and number<br />\n");
$result = $sth->fetch(PDO::FETCH_BOTH);
print_r($result);
print("<br />\n");
print("\n");

print("PDO::FETCH_LAZY: ");
print("Return next row as an anonymous object with column names as properties<br />\n");
$result = $sth->fetch(PDO::FETCH_LAZY);
print_r($result);
print("<br />\n");
print("\n");

print("PDO::FETCH_OBJ: ");
print("Return next row as an anonymous object with column names as properties<br />\n");
$result = $sth->fetch(PDO::FETCH_OBJ);
print_r($result);
print 'user_id:' . $result->user_id;
print("<br />\n");
print("\n");

print "<hr />\n";
//=======================================================

//=======================================================
function readDataForwards($dbh) {
  $sql = 'SELECT user_id,email,token FROM 99game_user limit 10';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR, PDO::CURSOR_SCROLL));
    $stmt->execute();
    while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "<br />\n";
      print $data;
    }
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}

function readDataBackwards($dbh) {
  $sql = 'SELECT user_id,email,token FROM 99game_user limit 10';
  try {
    $stmt = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
    $stmt->execute();
    $row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_LAST);
    do {
      $data = $row[0] . "\t" . $row[1] . "\t" . $row[2] . "<br />\n";
      print $data;
    } while ($row = $stmt->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_PRIOR));
    $stmt = null;
  }
  catch (PDOException $e) {
    print $e->getMessage();
  }
}

print "Reading forwards:<br />\n";
readDataForwards($dbh);

print "<hr />\n";

print "Reading backwards:<br />\n";
//下面的數據沒有按照想像中的倒排輸出，暫時不知道什么原因，php.net官方手冊中的例子也是這么寫的
readDataBackwards($dbh);
//=======================================================
?>

以上測試程序輸出如下：

Array
(
[user_id] => 1
[email] => [e-mail]
[token] => 123token456_73940
)

Array
(
[user_id] => 2
[email] => [e-mail]
[token] => 33fadfasdfadsf
)

PDO::FETCH_ASSOC: Return next row as an array indexed by column name
Array
(
[user_id] => 1
[email] => [e-mail]
[token] => 123token456_73940
)

PDO::FETCH_BOTH: Return next row as an array indexed by both column name and number
Array
(
[user_id] => 2
[0] => 2
[email] => [e-mail]
[1] => [e-mail]
[token] => 33fadfasdfadsf
[2] => 33fadfasdfadsf
)

PDO::FETCH_LAZY: Return next row as an anonymous object with column names as properties
PDORow Object
(
[queryString] => SELECT user_id,email,token FROM 99game_user limit 10
[user_id] => 3
[email] => [e-mail]
[token] => 123token456_61039
)

PDO::FETCH_OBJ: Return next row as an anonymous object with column names as properties
stdClass Object
(
[user_id] => 6
[email] => [e-mail]
[token] => cU8ady73epcmf54o7W0q1F0f8R3b2y4d
)
user_id:6

Reading forwards:
1 [e-mail] 123token456_73940
2 [e-mail] 33fadfasdfadsf
3 [e-mail] 123token456_61039
6 [e-mail] cU8ady73epcmf54o7W0q1F0f8R3b2y4d
7 [e-mail] 1wcl3j1a92bgc6eb8Y9rcQbjen5I8f7F
8 [e-mail] 90debU1x3ddWdSdc239hdF2t1AeScf3w
9 [e-mail] 1V1D8xao3O9m1mdq5706716kbx5u6n58
10 [e-mail] b28de59ddc824ed8a8556514dd83c348
11 [e-mail] 965e5873e6dbba4af57b96dfe0b027e7
12 [e-mail]_69054 123token456_69054

Reading backwards:
1 [e-mail] 123token456_73940
2 [e-mail] 33fadfasdfadsf
3 [e-mail] 123token456_61039
6 [e-mail] cU8ady73epcmf54o7W0q1F0f8R3b2y4d
7 [e-mail] 1wcl3j1a92bgc6eb8Y9rcQbjen5I8f7F
8 [e-mail] 90debU1x3ddWdSdc239hdF2t1AeScf3w
9 [e-mail] 1V1D8xao3O9m1mdq5706716kbx5u6n58
10 [e-mail] b28de59ddc824ed8a8556514dd83c348
11 [e-mail] 965e5873e6dbba4af57b96dfe0b027e7
12 [e-mail]_69054 123token456_69054

延伸閱讀：
http://www.baidu.com/s?wd=php%20pdo%20%E4%BC%98%E7%82%B9
http://www.sogou.com/web?query=php%20pdo%20優點
https://www.so.com/s?q=php%20pdo%20%E4%BC%98%E7%82%B9
http://www.open-open.com/lib/view/open1419950418859.html
PHP5中PDO的簡單使用
http://blog.csdn.net/leo115/article/details/7538983

php pdo操作數據庫
http://www.cnblogs.com/yujon/p/5476176.html

為什么 PHP 應該使用 PDO 方式訪問數據庫
http://www.php100.com/html/itnews/PHPxinwen/2013/0618/13555.html

PDO預處理語句PDOStatement對象使用總結
http://www.jb51.net/article/57609.htm