PHP登录和注册错误

Question

The error shown is

"Fatal error: Uncaught Error: Call to a member function query() on string in D:\Users\kukor\Documents\XAMPP\htdocs\timetable\class.ManageUsers.php:22 Stack trace: #0 D:\Users\kukor\Documents\XAMPP\htdocs\timetable\login.php(19): ManageUsers->LoginUsers('kayzmark', 'ultimate') #1 {main} thrown in D:\Users\kukor\Documents\XAMPP\htdocs\timetable\class.ManageUsers.php on line 22"

<?php
class ManageUsers{
    public $link;

    function __construct(){
        $db_connection = new dbConnection();
        $this->link = $db_connection->connect();
        return $this->link;
    }

    function registerUsers($password, $ip_address, $date, $time, $username, $email, $uname){
        $query = $this->link->prepare("INSERT INTO users (password,ip_address,date,time,username, email, uname) VALUES(?,?,?,?,?,?,?)");
        $values = array ($password, $ip_address, $date, $time, $username, $email, $uname);
        $query->execute($values);
        $count = $query->rowCount();
        return $count;
    }

    function LoginUsers($username, $password){
        $query = $this->link->query("SELECT * FROM users WHERE username='$username' AND password='$password'");
        $rowCount = $query->rowCount();
        return $rowCount;
    }

    function GetUserInfo($username){
        $query = $this->link->query("SELECT * FROM users WHERE username = '$username'");
        $rowCount = $query->rowCount();
        if($rowCount ==1)
        {
            $result = $query->fetchAll();
            return $result;
        }
        else
        {
            return $rowCount;
        }
    }
}
?>

Answer 1

You are probaly calling ->query() on a string instead of the object. Could you verify that the variable where you call query() on contains the right object and you are not overriding it by mistake?