PHP连接数据库的另外一种方法PDO

大家连接数据库大多数应该用的都是mysql_connect()这样的吧，当然，肯定也有不是的啊，在php5以后的版本中增加了mysqli_connect()，这样的比mysql_connect()高效，其实这其中还带有一个php自己写的内置类  $conn=new mysqli()，我记得是这样的，大家可以试试看，在这里我要说的不是这些连接方法，而是另外一种即PDO来连接数据库
具体方法我整理出来，和大家分享一下，共同进步！

/**
*需要加载pdo模块，找到
 ;extension=php_pdo.dll
 ;extension=php_pdo_firebird.dll
 ;extension=php_pdo_mssql.dll
 ;extension=php_pdo_mysql.dll
 ;extension=php_pdo_oci.dll
 ;extension=php_pdo_oci8.dll
 ;extension=php_pdo_odbc.dll
 ;extension=php_pdo_pgsql.dll
 ;extension=php_pdo_sqlite.dll
把前面的;都去掉，相信这个大家都会的就不多说
*/

eg1、Connecting to mysql

<?php
$dbh = newPDO('mysql:host=localhost;dbname=test',  $user, $pass);
?>

eg2、Handling connection errors

<?php
try {
$dbh = new PDO('mysql:host=localhost;dbname=test',  $user, $pass);
foreach ($dbh->query('SELECT * from FOO') as $row) {
print_r($row);
}
$dbh = null;
} catch (PDOException $e) {
print  "Error!: " . $e->getMessage() . "<br/>";
die();
}
?>  

eg3、Closing a connection

<?php
$dbh = newPDO('mysql:host=localhost;dbname=test',  $user, $pass);
// use the connection here

// and now we're done; close  it
$dbh = null;
?>

eg4、Persistent connections 永久连接

<?php
$dbh = new PDO('mysql:host=localhost;dbname=test',  $user, $pass, array(PDO_ATTR_PERSISTENT =>  true
));  

eg5、Executing a batch in a transaction  在事务中的批处理执行

<?php
try {
$dbh = new PDO ('odbc:SAMPLE', 'db2inst1', 'ibmdb2', 
array(PDO_ATTR_PERSISTENT =>  true));
echo  "Connected\n";
$dbh->setAttribute(PDO_ATTR_ERRMODE, PDO_ERRMODE_EXCEPTION);

$dbh->beginTransaction();
$dbh->exec("insert into staff (id, first, last)  values (23, 'Joe', 'Bloggs')");
$dbh->exec("insert  into salarychange (id, amount, changedate) 
values (23, 50000,  NOW())");
$dbh->commit();

} catch (Exception $e) {
$dbh->rollBack();
echo "Failed: " . $e->getMessage();
}
?> 

eg6、Repeated inserts using prepared statements -1 重复使用准备好的语句插入(即绑定参数)

<?php
$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value)  VALUES (:name, :value)");
$stmt->bindParam(':name', $name);
$stmt->bindParam(':value', $value);

// insert one row
$name = 'one';
$value = 1;
$stmt->execute();

// insert another row with  different values
$name = 'two';
$value = 2;
$stmt->execute();
?> 

eg7、Repeated inserts using prepared statements -2

<?php
$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value)  VALUES (?, ?)");
$stmt->bindParam(1, $name);
$stmt->bindParam(2, $value);

// insert one row
$name = 'one';
$value = 1;
$stmt->execute();

// insert another row with  different values
$name = 'two';
$value = 2;
$stmt->execute();
?> 

eg8、 Fetching data using prepared statements 提取数据使用准备好的语句
(这个例子对获取的形式提供一个键值的数据。用户输入是自动进行加引号，所以不存在一个SQL注入攻击的危险)

<?php
$stmt = $dbh->prepare("SELECT * FROM REGISTRY where name =  ?");
if ($stmt->execute(array($_GET['name']))) {
while ($row = $stmt->fetch()) {
print_r($row);
}
}
?> 

最后我提供一点自己写的程序，不熟悉的朋友相信有点用的呀，会的就可以不看啦

<?php
//插入数据
try {
   $dbh = new PDO('mysql:host=localhost;dbname=gbook',"root","123456");

/*
*第一种方法：
*/   
$stmt = $dbh->prepare("INSERT INTO guestbook(title, name, contents)  VALUES (:title,:name,:contents)");
   $title = 'Hello';
   $name = "CWL";
   $contents="Hello World!";
   $stmt->execute(array(':title' => $title, ':name' => $name,'contents'=>$contents));

/*
此为第二种方法，也可，与上种方法相比，省去对 $stmt->bindParam() 的调用。
   $stmt = $dbh->prepare("INSERT INTO guestbook(title, name, contents)  VALUES (:title,:name,:contents)");
   $title = 'Hello';
   $name = "CWL";
   $contents="Hello World!";
   $stmt->bindParam(':title', $title);
   $stmt->bindParam(':name', $name);
   $stmt->bindParam(':contents', $contents);
   $stmt->execute();
*/
} catch (PDOException $e) {
    print  "Error!: " . $e->getMessage() . "<br/>";
    die();
}

//查询数据
/*
try {
    foreach ($dbh->query('SELECT * from guestbook') as $row) {
        print_r($row);
    }
    $dbh = null;
} catch (PDOException $e) {
    print  "Error!: " . $e->getMessage() . "<br/>";
    die();
}
*/
?>

本文来自：http://hi.baidu.com/caowlong/blog/item/ea650c464d942441510ffeb7.html

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