想不通，我在準備好的聲明

Question

我目前正在轉換這段代碼從MySQL到PDO做什麼錯誤：

$catquery = mysql_query("SELECT category, longdescription, locked, 
           catid, parentcatid, leveldown 
         FROM ".$tableprefix."fanfiction_categories 
         WHERE catid = '$catid'") 
       or die(_FATALERROR."Query: SELECT category, locked, catid, parentcatid, leveldown FROM ".$tableprefix."fanfiction_categories WHERE catid = '$catid'<br />Error: (".mysql_errno().") ".mysql_error()); 
$category = mysql_fetch_array($catquery); 

我是新來的PDO，但一直在努力學習我能做什麼。這是我在PDO中想到的：

$db = new PDO('mysql:host='.$db_host.'; dbname='.$db_name, $db_user, $db_pass); 
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
$catquery = $db->prepare("SELECT category, longdescription, locked, catid, 
           parentcatid, leveldown 
          FROM ".$tableprefix."fanfiction_categories 
          WHERE catid=:catid"); 
$stmt -> bindPARAM (':catid', $catid, PDO::PARAM_STR); 
try { 
    $stmt->execute(); 
    echo "Sucess"; 
} catch (PDOException $e) { 
     echo $e->getMessage(); 
} 

即使嘗試了很多形式，我仍無法獲得正確的bindPARAM部分。有我忽略的東西嗎？關於PDO，我有點困惑，所以如果有人能指出我在哪裏出錯，這將是很好的。

Answer 1

很簡單，你已經忘記從你的副本修改所有的變量/粘貼

$db = new PDO('mysql:host='.$db_host.'; dbname='.$db_name, $db_user, $db_pass); 
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
$catquery = $db->prepare("SELECT category, longdescription, locked, catid, 
           parentcatid, leveldown 
          FROM ".$tableprefix."fanfiction_categories 
          WHERE catid=:catid"); 

//$stmt -> bindPARAM (':catid', $catid, PDO::PARAM_STR); 
$catquery -> bindPARAM (':catid', $catid, PDO::PARAM_STR); 
try { 

    //$stmt->execute(); 
    $catquery->execute(); 

    echo "Sucess"; 
} catch (PDOException $e) { 
     echo $e->getMessage(); 
}