这里是有问题的代码:
来自 index.php:
require_once('includes/DbConnector.php');
// Create an object (instance) of the DbConnector
$connector = new DbConnector();
// Execute the query to retrieve articles
$query1 = "SELECT id, title FROM articles ORDER BY id DESC LIMIT 0,5";
$result = $connector->query($query1);
echo "vardump1:";
var_dump($result);
echo "\n";
/*(!line 17!)*/ echo "Number of rows in the result of the query:".mysql_num_rows($result)."\n";
// Get an array containing the results.
// Loop for each item in that array
while ($row = $connector->fetchArray($result)){
echo '<p> <a href="viewArticle.php?id='.$row['id'].'">';
echo $row['title'];
echo '</a> </p>';
来自 dbconnector.php:
$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'];
// Connect to the database
$this->link = mysql_connect($host, $user, $pass);
mysql_select_db($db);
register_shutdown_function(array(&$this, 'close'));
} //end constructor
//*** Function: query, Purpose: Execute a database query ***
function query($query) {
echo "Query Statement: ".$query."\n";
$this->theQuery = $query;
return mysql_query($query, $this->link) or die(mysql_error());
}
//*** Function: fetchArray, Purpose: Get array of query results ***
function fetchArray($result) {
echo "<|";
var_dump($result);
echo "|> \n";
/*(!line 50!)*/$res= mysql_fetch_array($result) or die(mysql_error());
echo $res['id']."-".$res['title']."-".$res['imagelink']."-".$res['text'];
return $res;
}
输出:
Query Statement: SELECT id, title FROM articles ORDER BY id DESC LIMIT 0,5 vardump1:bool(true)
PHP Error Message
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /*path to*/index.php on line 17
Number of rows in the result of the query: <|bool(true) |>
PHP 错误信息
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /*path to*/DbConnector.php on line 50
最佳答案
您的问题出在下一行:
return mysql_query($query, $this->link) or die(mysql_error())
应该这样写:
$result = mysql_query($query, $this->link);
if(!$result) die(mysql_error());
return $result;
在动态语言中,or
返回第一个评估为 true 的 object
是很常见的,但在 PHP 中,X 或 Y
的结果是始终为 true 或 false。
关于php - mysql_query() 返回返回 true,但 mysql_num_rows() 和 mysql_fetch_array() 给出“不是有效资源错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3009035/