prepare函数使用错误 - prepare function used wrong?

prepare function used wrong?

本文关键字：错误函数 prepare | 更新日期: 2023-09-27

任何人都知道我为什么会出现这个错误：

Call to a member function prepare() on a non-object

对于这个代码片段：

public function check_availability($dataID) {
    $query = "SELECT dump FROM dumps WHERE dump = '".$dataID."'";
    if ($stmt = $mysqli->prepare($query)) {
        $stmt->execute();
        if($stmt->rowCount() > 0) {
            return FALSE;
        } else {
            return TRUE;
        }
        $stmt->close();
    }
}

尤其是这条线：

if ($stmt = $mysqli->prepare($query)) {

变量$mysqli不会错，因为：

$mysqli = new mysqli($config['sql_hostname'], $config['sql_username'], $config['sql_password'], $config['sql_database']);

更新：

我在浏览器中调用这个脚本：

define('SECURE', true);
include "storescripts/connect_to_mysql.php";
require 'AvailabilityChecker.php';
$config = array('DB' => $mysqli,
                'Table' => 'dumps',
                'Row' => 'dump',
                'Output' => true,
                'Format' => 'JSON');
$availabilityChecker = new AvailabilityChecker($config);
if($availabilityChecker->check_availability($_POST['dataID'])) {
    echo "ok";
} else {
    echo "not ok";
}

$mysqli是在"connect_to_mysql.php"中定义的，那么呢？

您应该创建mysqli的Object并检查结果

$mysqli = new mysqli("localhost", "username", "password", "dbname");
if(!$mysqli)
{
   die("can not access the db");
}

然后你可以使用功能

$mysqli->prepare($query)