PHP应用：PHP5.2中PDO的简单使用方法

CREATE TABLE tablename (
  id mediumint(8) UNSIGNED NOT NULL AUTO_INCREMENT,
  str varchar(50) NOT NULL DEFAULT '''',
  PRIMARY KEY (id)
);

<?php
$dsn = "mysql:host=localhost;dbname=test";
$user = ''root'';
$passwd = ''123456'';
try{
    $db = new PDO($dsn, $user, $passwd);
}catch (PDOException $e)
{
    echo "链接数据库失败!";
    print "异常信息: ". $e->getMessage() . "<br/>";
    print "异常文件: " . $e->getFile() . "<br/>";
    print "异常行号: " . $e->getLine() . "<br/>";
    exit();
}
//$sql = "INSERT INTO tablename SET str = ''Hello''";
//$count = $db->exec($sql); //返回值为影响的行数
//$sql = "DELETE FROM tablename WHERE str = ''Hello'' LIMIT 1";
//$count = $db->exec($sql); //返回值为影响的行数
//预处理需要查询的SQL语句
//$db->setAttribute(PDO::ATTR_CASE, PDO::CASE_NATURAL); //列名依照原始的方式(字段)
$sql = "SELECT * FROM tablename WHERE id < :id AND str = :string"; //sql语句(参数绑定方式)
$query = $db->prepare($sql); //预处理
//用一组绑定参数执行一遍查询
$query->execute(array('':id''=>1, '':string''=>''Hello'')); //处理语句(参数绑定方式)
//$query->setFetchMode(PDO::FETCH_ASSOC); 关联数组形式(只通过字段名下标访问数组内容)
while($item = $query->fetch(PDO::FETCH_ASSOC)) //循环获取数据
{
    echo $item[''id''].":".$item[''str'']."<br/>";
    //print_r ($item);
}
//用另一组绑定参数,再执行一遍查询
$query->execute(array('':id''<=10, '':string''=>''HelloWorld'')); //处理语句(参数绑定方式)
//$query->setFetchMode(PDO::FETCH_ASSOC); 关联数组形式(只通过字段名下标访问数组内容)
while($item = $query->fetch(PDO::FETCH_ASSOC)) //循环获取数据
{
    echo $item[''id''].":".$item[''str'']."<br/>";
    //print_r ($item);
}
$db = null; //释放数据库链接
?>