警告：mysql_fetch_array（）：提供的參數不是有效的MySQL結果我在嘗試運行時遇到錯誤：<?phprequire_once('includes/DbConnector.php');$connector = new DbConnector();$result = $connector->query('SELECT title,content FROM staff_vacancies ORDER BY ordering LIMIT 0,100');// Get an array containing the results.// Loop for each item in that arraywhile ($row = $connector->fetchArray($result)){echo $row['title'].'</h3>';echo $row['content'];}?>我有一個鏈接文件：DbConnector.php：<?php////////////////////////////////////////////////////////////////////////////////////////// Class: DbConnector// Purpose: Connect to a database, MySQL version///////////////////////////////////////////////////////////////////////////////////////require_once 'SystemComponent.php';class DbConnector extends SystemComponent {var $theQuery;var $link;//*** Function: DbConnector, Purpose: Connect to the database ***function DbConnector(){    // Load settings from parent class    $settings = SystemComponent::getSettings();    // Get the main settings from the array we just loaded    $host = $settings['dbhost'];    $db = $settings['dbname'];    $user = $settings['dbusername'];    $pass = $settings['dbpassword'];    //the settings    $host = 'localhost';    $db = 'xxx';    $user = 'xxx';    $pass = 'xxx';    // Connect to the database    $this->link = mysql_connect($host, $user, $pass);    mysql_select_db($db);    register_shutdown_function(array(&$this, 'close'));}//*** Function: query, Purpose: Execute a database query ***function query($query) {    $this->theQuery = $query;    return mysql_query($query, $this->link);}//*** Function: getQuery, Purpose: Returns the last database query, for debugging ***function getQuery() {    return $this->theQuery;}//*** Function: getNumRows, Purpose: Return row count, MySQL version ***function getNumRows($result) {    return mysql_num_rows($result);}//*** Function: fetchArray, Purpose: Get array of query results ***function fetchArray($result) {    return mysql_fetch_array($result);}有誰知道問題是什么？