PDO單例模型

<?php/** * ipdo.php * * discription * * @filename ipdo.php * @version  v1.0 * @update   2011-4-27 * @author   randy.hong * @contact homingway@163.com * @package  pdo *///DB configdefine('DB_HOST',   'localhost');define('DB_PORT',   '3306');define('DB_USER',   'root');define('DB_PASSWD', '123456');define('DB_CHARSET','utf8');class IPDO {    /**     * The singleton instance     */    static public $PDOInstance;  /**   * Creates a PDO instance representing a connection to a database and makes the instance available as a singleton   * @return PDO   */    public function __construct(){    $dsn = 'mysql:host='.DB_HOST.';port='.DB_PORT.';dbname='.DB_NAME;    $driver_options = array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES ".DB_CHARSET);        if(!self::$PDOInstance) {       try {               self::$PDOInstance = new PDO($dsn, DB_USER, DB_PASSWD, $driver_options);               self::$PDOInstance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);            } catch (PDOException $e) {                die($e->getMessage());            }    }      return self::$PDOInstance;    }}//使用$pdo = new IPDO();?>

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