PHP-访问对象属性$ id时出错

Question

I am following a tutorial about how to make register form with database connection but for some reason the code does not work for me. I do not know what I am doing wrong so maybe someone can point it out for me.

This is the code on the User.php file:

<?php
class User {
    private $_db,
            $_data,
            $_sessionName;

    public function __construct($user = null) {
        $this->_db = DB::getInstance();

        $this->_sessionName = Config::get('session/session_name');
    }

    public function create($fields = array()) {
        if(!$this->_db->insert('users', $fields)) {
            throw new Exception('There was a problem creating an account.');
        }
    }

    public function find($user = null) {
        if($user) {
            $field = (is_numeric($user)) ? 'id' : 'username';
            $data = $this->_db->get('users', array($field, '=', $user));

            if($data->count()) {
                $this->_data = $data->first();
                return true;
            }
        }
        return false;
    }

    public function login($username = null, $password = null) {
        $user = $this->find($username);

        if($user) {
            if($this->data()->password === Hash::make($password, $this->data()->salt)) {
                Session::put($this->_sessionName, $this->data()->id);
                return true;
            }
        }
        return false;
    }

    private function data() {
        return $this->_data;
    }
}
?>

Getting this error back:

Notice: Undefined property: stdClass::$id in /opt/lampp/htdocs/rd-website/classes/User.php on line 37

Line 37 is: Session::put($this->_sessionName, $this->data()->id);

Any help?

Answer 1

The problem was that i had the column named "ID" in the users table in the database, while in the User.php file it was written as "id".

Since Mysql is case insensitive if you are running on Windows that wouldn't be a problem or give any errors back, but for some Unix systems it's case sensitive, I run Kali-Linux so that was giving a error back.

I just changed the column "ID" to "id" in the database, as it was the easiest thing to do for this time and now the code works perfectly.

If you are looking for a permanent solution then you would have to change the "my.cnf" file,

under LAMPP/XAMPP... :

/opt/lampp/etc/my.cnf

stand alone mysql server :

/etc/mysql/my.cnf

with this line (lower_case_table_names = 1) You can change either to = 0,1 or 2 but that depends on your system and your needs.

After that you would need to restart the service again.