致命错误:调用未定义的方法 Database::prepare()
我为数据库和用户创建了一个单独的类.
I have created a separate class for database and users.
数据库.php
class Database{
private $db;
public function __construct(){
/*** mysql hostname ***/
$hostname = 'localhost';
/*** mysql username ***/
$username = 'username_web';
/*** mysql password ***/
$password = 'password_web';
try {
$this->db = new PDO("mysql:host=$hostname;dbname=kamadhenu_web", $username, $password);
/*** echo a message saying we have connected ***/
}
catch(PDOException $e)
{
echo $e->getMessage();
}
}
/*** Query Function ***/
public function query($sql)
{
return $this->db->query($sql);
}
}
Users.php
class Users{
private $db;
public function __construct($database) {
$this->db = $database;
}
public function login($username, $password)
{
$query=$this->db->prepare("SELECT `password`, `id` FROM `users` WHERE `username` = ?");
$query->bindValue(1, $username);
try{
$query->execute();
$data = $query->fetch();
$stored_password = $data['password'];
$id = $data['id'];
#hashing the supplied password and comparing it with the stored hashed password.
if($stored_password === sha1($password)){
return $id;
}else{
return false;
}
}catch(PDOException $e){
die($e->getMessage());
}
}
}
这是我的登录页面，包含用户名和密码.
Here is my Login page with username and password.
login.php
include('database.php');
include('users.php');
$dbh= new Database();
$users= new Users($dbh);
if (isset($_POST['submit']))
{
$username= $_POST['username'];
$password= $_POST['password'];
$login = $users->login($username, $password);
if ($login === false) {
$errors[] = 'Sorry, that username/password is invalid';
}
else {
// username/password is correct and the login method of the $users object returns the user's id, which is stored in $login.
$_SESSION['id'] = $login; // The user's id is now set into the user's session in the form of $_SESSION['id']
#Redirect the user to home.php.
header('Location: list-updates.php');
exit();
}
}
执行时出现错误:
调用未定义的方法 Database::prepare()
Call to undefined method Database::prepare()
推荐答案
您在实例化 Database() 时创建了 $dbh，但是实例化 Database 只会返回您的 Database 类的实例，而不是您的数据库连接.您应该有一个 getDb 来从数据库对象获取连接:
You create $dbh when you instantiate Database(), but instantiating the Database only returns an instance of your Database class, not your db connection. You should have a getDb to get your connection from database object:
$dbClass = new Database();
$dbh = $dbClass->getDb(); // here you get the connection
$users= new Users($dbh); // here you give to Users() the $dbh, that isn't your
// connection.. it's just Database class
数据库构造仅返回数据库类的实例，而不返回数据库连接
class Database{
private $db;
public function __construct(){
try {
$this->db = new PDO("mysql:host=$hostname;dbname=kamadhenu_web", $username, $password);
/*** echo a message saying we have connected ***/
}
catch(PDOException $e)
{
echo $e->getMessage();
}
}
public function getDb() {
if ($this->db instanceof PDO) {
return $this->db;
}
}
}
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