在php中插入mysql中的值时出错

Question

这是我的代码

  if (empty($_POST['username']) || empty($_POST['password'])) { $response["success"] = 0; $response["message"] = "Please Enter Both a Username and Password."; die(json_encode($response)); } $query = " SELECT 1 FROM users WHERE username = :user"; $query_params = array( ':user' => $_POST['username'] ); //////////////////////////////////////////////////////////////////////////////////////////////////////////ERROR//////////////////////////////////////////////////////// try { $stmt = $db->prepare($query); $result = $stmt->execute($query_params); } catch (PDOException $ex) { $response["success"] = 0; $response["message"] = "Database Error1. Please Try Again!"; die(json_encode($response)); } $row = $stmt->fetch(); if ($row) { $response["success"] = 0; $response["message"] = "I'm sorry, this username is already in use"; die(json_encode($response)); } $query = "INSERT INTO users ( username, password ) VALUES ( :user, :pass ) "; $query_params = array( ':user' => $_POST['username'], ':pass' => $_POST['password'] ); try { $stmt = $db->prepare($query); $result = $stmt->execute($query_params); } catch (PDOException $ex) { $response["success"] = 0; $response["message"] = "Database Error2. Please Try Again!"; die(json_encode($response)); } $response["success"] = 1; $response["message"] = "Username Successfully Added!"; echo json_encode($response); } else { ?> <h1>Register</h1> <form action="register.php" method="post"> Username:<br /> <input type="text" name="username" value="" /> <br /><br /> Password:<br /> <input type="password" name="password" value="" /> <br /><br /> <input type="submit" value="Register New User" /> </form> <?php }      ？＆GT;

我已将该行标记为错误。这是错误。我安装了wamp服务器，这是我跟随mybringback的教程的链接，然后查看register.php v.02

这是config.php的内容

<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
 * Front controller for config view / download and clear
 *
 * @package PhpMyAdmin-Setup
 */

/**
 * Core libraries.
 */
require './lib/common.inc.php';
require_once './libraries/config/Form.class.php';
require_once './libraries/config/FormDisplay.class.php';
require_once './setup/lib/ConfigGenerator.class.php';

require './libraries/config/setup.forms.php';

$form_display = new FormDisplay();
$form_display->registerForm('_config.php', $forms['_config.php']);
$form_display->save('_config.php');
$config_file_path = ConfigFile::getInstance()->getFilePath();

if (isset($_POST['eol'])) {
    $_SESSION['eol'] = ($_POST['eol'] == 'unix') ? 'unix' : 'win';
}

if (PMA_ifSetOr($_POST['submit_clear'], '')) {
    //
    // Clear current config and return to main page
    //
    ConfigFile::getInstance()->resetConfigData();
    // drop post data
    header('HTTP/1.1 303 See Other');
    header('Location: index.php');
    exit;
} elseif (PMA_ifSetOr($_POST['submit_download'], '')) {
    //
    // Output generated config file
    //
    PMA_downloadHeader('config.inc.php', 'text/plain');
    echo ConfigGenerator::getConfigFile();
    exit;
} elseif (PMA_ifSetOr($_POST['submit_save'], '')) {
    //
    // Save generated config file on the server
    //
    file_put_contents($config_file_path, ConfigGenerator::getConfigFile());
    header('HTTP/1.1 303 See Other');
    header('Location: index.php?action_done=config_saved');
    exit;
} elseif (PMA_ifSetOr($_POST['submit_load'], '')) {
    //
    // Load config file from the server
    //
    $cfg = array();
    include_once $config_file_path;
    ConfigFile::getInstance()->setConfigData($cfg);
    header('HTTP/1.1 303 See Other');
    header('Location: index.php');
    exit;
} elseif (PMA_ifSetOr($_POST['submit_delete'], '')) {
    //
    // Delete config file on the server
    //
    @unlink($config_file_path);
    header('HTTP/1.1 303 See Other');
    header('Location: index.php');
    exit;
} else {
    //
    // Show generated config file in a <textarea>
    //
    header('HTTP/1.1 303 See Other');
    header('Location: index.php?page=config');
    exit;
}
?>

Answer 1

$stmt   = $db->prepare($query);

您正在创建一个语句，但您没有首先创建PDO对象$db。无处可见。它必须按此顺序

$db = new PDO($dsn, $user, $password);
$stmt   = $db->prepare($query);

来自PHP.net的示例代码，可帮助您解释如何创建PDO对象

<?php
$dsn = 'mysql:dbname=testdb;host=127.0.0.1';   //replace 'dbname' with your database name
$user = 'dbuser';    // whats your database username?
$password = 'dbpass';  // database password?

try {
    $dbh = new PDO($dsn, $user, $password);
} catch (PDOException $e) {
    echo 'Connection failed: ' . $e->getMessage();
}

?>