مشکل در کار با pdo

[soroush.r70]

من یک کلاسی برای کار با دیتابیس دارم با استفاده از pdo که برای select کردن اطلاعاتم نمی دونم چرا کار نمی کنه مشکل کجاست دوستان...؟

class.php


<?php
class content
{
private $host = DB_HOST;
private $user = DB_USER;
private $pass = DB_PASS;
private $dbname = DB_NAME;

private $dbh;
private $error;

public function __construct(){
// Set DSN
$dsn = 'mysql:host=' . $this->host . ';dbname=' . $this->dbname;
// Set options
$options = array(
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"
);
// Create a new PDO instanace
try{
$this->dbh = new PDO($dsn, $this->user, $this->pass, $options);
/*** close the database connection ***/
$this->dbh = null;

}
// Catch any errors
catch(PDOException $e){
$this->error = $e->getMessage();
}
}





// query
public function query($query){
$this->stmt = $this->dbh->prepare($query);
}


public function bind($param, $value, $type = null){
if (is_null($type)) {
switch (true) {
case is_int($value):
$type = PDO::PARAM_INT;
break;
case is_bool($value):
$type = PDO::PARAM_BOOL;
break;
case is_null($value):
$type = PDO::PARAM_NULL;
break;
default:
$type = PDO::PARAM_STR;
}
}
$this->stmt->bindValue($param, $value, $type);
}



public function execute(){
return $this->stmt->execute();
}




public function resultset(){
$this->execute();
return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
}





public function single(){
$this->execute();
return $this->stmt->fetch(PDO::FETCH_ASSOC);
}




public function rowCount(){
return $this->stmt->rowCount();
}



public function lastInsertId(){
return $this->dbh->lastInsertId();
}




public function beginTransaction(){
return $this->dbh->beginTransaction();
}



public function endTransaction(){
return $this->dbh->commit();
}



public function cancelTransaction(){
return $this->dbh->rollBack();
}


public function debugDumpParams(){
return $this->stmt->debugDumpParams();
}



///date copyright
public function copyright($year = 'auto'){
if(intval($year) == 'auto'){ $year = date('Y'); }
if(intval($year) == date('Y')){ echo intval($year); }
if(intval($year) < date('Y')){ echo intval($year) . ' - ' . date('Y'); }
if(intval($year) > date('Y')){ echo date('Y'); }
}


//get ip
public function getip()
{
if (!empty($_SERVER['HTTP_CLIENT_IP']))
{
$ip=$_SERVER['HTTP_CLIENT_IP'];
}
elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
{
$ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
}
else
{
$ip=$_SERVER['REMOTE_ADDR'];
}
return $ip;
}



}
?>


function.php


<?php
error_reporting(E_ALL);
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
define("DB_HOST", "localhost");
define("DB_USER", "root");
define("DB_PASS", "");
define("DB_NAME", "db_baa");
require_once 'class.php';
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function slider()
{
$class=new content;
$class->query('select * from `tbl_slider` order by `id` desc ');
while($row=$class->single())
{
echo'
<li style="slidedelay: 5000; transition2d: 92,93,105;" > <img src="upload/'.$row['pic'].'" alt="" />
<div class="wrapper">
<div class="caption lfb huge" data-x="center" data-y="100" data-speed="900" data-start="100" data-easing="easeOutSine">دردست ساخت</div>
<div class="caption lft p-text-slider-2" data-x="center" data-y="200" data-speed="900" data-start="900" data-easing="easeOutSine">سایت در دست ساخت می باشد</div>
<!--<a href="#" class="caption sfr b-slider" data-x="20" data-y="410" data-speed="300" data-start="1400" data-easing="easeOutExpo">اطلاعات بیشتر</a>-->
</div>
</li>
';

}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

?>


index.php


<?php
define('__ROOTF__', dirname(__FILE__));
require_once(__ROOTF__.'/inc/function.php');
slider();
?>



لطف می کنید بگید بگید مشکل کجاست خیلی واجبه وقت ندارم ممنون

[Veteran]

$this->dbh = new PDO($dsn, $this->user, $this->pass, $options); /*** close the database connection ***/ $this->dbh = null;
چرا null دادین کانکشن رو ؟ علت چیه ؟
خب دیگه ارتباط قطع میشه با این وضعیت :متفکر:

[soroush.r70]

خوب null هم بردارم جواب نمی ده چرا...؟

[Veteran]

این یک نمونه با استفاده از کده شما که من تست کردم و جواب گرفتم

<?php
class content
{
private $host = DB_HOST;
private $user = DB_USER;
private $pass = DB_PASS;
private $dbname = DB_NAME;

private $stmt;
private $dbh;
private $error;

public function __construct(){
// Set DSN
$dsn = 'mysql:host=' . $this->host . ';dbname=' . $this->dbname;
// Set options
$options = array(
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"
);
// Create a new PDO instanace
try{
$this->dbh = new PDO($dsn, $this->user, $this->pass, $options);
/*** close the database connection ***/


}
// Catch any errors
catch(PDOException $e){
$this->error = $e->getMessage();
}
}





// query
public function query($query){
$this->stmt = $this->dbh->prepare($query);
}


public function bind($param, $value, $type = null){
if (is_null($type)) {
switch (true) {
case is_int($value):
$type = PDO::PARAM_INT;
break;
case is_bool($value):
$type = PDO::PARAM_BOOL;
break;
case is_null($value):
$type = PDO::PARAM_NULL;
break;
default:
$type = PDO::PARAM_STR;
}
}
$this->stmt->bindValue($param, $value, $type);
}



public function execute(){
$this->stmt->execute();
}




public function resultset(){
$this->execute();
return $this->stmt->fetchAll(PDO::FETCH_ASSOC);
}





public function single(){
$this->execute();
return $this->stmt->fetchAll(PDO::FETCH_ASSOC);

}




public function rowCount(){
return $this->stmt->rowCount();
}



public function lastInsertId(){
return $this->dbh->lastInsertId();
}




public function beginTransaction(){
return $this->dbh->beginTransaction();
}



public function endTransaction(){
return $this->dbh->commit();
}



public function cancelTransaction(){
return $this->dbh->rollBack();
}


public function debugDumpParams(){
return $this->stmt->debugDumpParams();
}



///date copyright
public function copyright($year = 'auto'){
if(intval($year) == 'auto'){ $year = date('Y'); }
if(intval($year) == date('Y')){ echo intval($year); }
if(intval($year) < date('Y')){ echo intval($year) . ' - ' . date('Y'); }
if(intval($year) > date('Y')){ echo date('Y'); }
}


//get ip
public function getip()
{
if (!empty($_SERVER['HTTP_CLIENT_IP']))
{
$ip=$_SERVER['HTTP_CLIENT_IP'];
}
elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))
{
$ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
}
else
{
$ip=$_SERVER['REMOTE_ADDR'];
}
return $ip;
}



}

error_reporting(E_ALL);
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
define("DB_HOST", "localhost");
define("DB_USER", "root");
define("DB_PASS", "");
define("DB_NAME", "test");

//////////////////

$class=new content;
$class->query('select * from `info`');
$result=$class->single();
foreach($result as $key => $value) {
echo $result[$key]['un'];
}

?>

[soroush.r70]

ممنون چرا نمی شه از همون while استفاده کرد مشکلش چیه..؟ روش بهینه تر کدومه...؟