PHP PDO更新準備好的語句問題

大家好我最近一直在嘗試我的PDO，我正在嘗試爲我正在開發的項目編寫一個基本的數據庫類。但是我遇到了一些問題，試圖編寫一個函數來執行使用預處理語句的更新查詢。PHP PDO更新準備好的語句問題

function update($tabledata, $table, $where){ 

    $fields = array_keys($tabledata); 
    $data = array_values($tabledata); 
    $fieldcount = count($fields); 

    $wherefield = implode(array_keys($where)); 
    $whereval = implode(array_values($where)); 

    $this->query = "UPDATE $table SET "; 
    $this->query .= '(' . implode($fields, ' = ?, ') . ' = ?)'; 
    $this->query .= " WHERE $wherefield = '$whereval'"; 

    $this->query = $this->_clean($this->query); 
    $stmt = $this->conn->prepare($this->query) or die('Problem preparing query'); 
    $stmt->execute($data)or die('Problem executing query'); 

}

它的一個例子是使用將是：

$usertbl = 'users'; 
$date = date("Y-m-d"); 
$updatedata = array(
    'Username' => 'test', 
    'Password' => 'unknown', 
    'Email' => 'email', 
    ); 
$where = array(
    'Username' => 'user' 
    ); 

$Database->update($updatedata,$usertbl,$where);

這將返回以下錯誤：

Warning: PDOStatement::execute() [pdostatement.execute]: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(Username = 'test', Password = 'unknown', Email = 'email') WHERE Username = 'use' at line 1

任何幫助將非常感激。

來源

2011-02-05 trottski