php / html5登录验证

Question

I am trying to authenticate a user in a MYsql database. I have tried so many tutorials to just fail every time. I am pasting my code below, I dont care about security or sql injection right now. I am just trying to get this to work so I can go on to my next requirement. If anybody has any links to a GOOD php/html5 login authentication tutorial then please share. I easily was able to create a registration form but this login form is really giving me difficulties.

$id =$_POST['Id'];
$password =$_POST['password'];
$accessdb = "SELECT * from UserData where Id ='$id' and password ='$password";
            $authenticate = mysqli_query($conn, $accessdb);
                    if (mysqli_num_rows($authenticate) == 1) {
                       session_start();
                        $_SESSION['auth'] = 'true';
                        header('location: Profile.php');
                    }
                    else {
                        echo "Wrong log-in credentials";
                    }

Answer 1

First of all, session_start() should be the very first thing on your page and should be on all the pages you want your user authenticated to get access to.

Then, you need to correct your query $accessdb like so:

$accessdb = "SELECT * FROM userdata WHERE id = {$id} AND password ='{$password}'";

NB : not sure if $id is a number. If it's not, then do: '{$id}' instead of {$id} .

Answer 2

        $password =$_POST['password'];
        $user = "SELECT * FROM UserData WHERE Id ='$id'";
        $authenticate = $conn->query($user);
        $row = $authenticate->fetch_assoc();
        $hash_password = $row['password'];
        $hash = password_verify($password, $hash_password);
        if ($hash ==0) {
            echo "Something went wrong!!";
            header('Location: LogIn.php');
            exit();
        }
        else {
       `enter code here`$accessdb = "SELECT * FROM UserData WHERE Id ='$id'                                                      
        AND    password = '$hash_password'";
            $authenticate = $conn->query($accessdb);
                if (!$row = $authenticate->fetch_assoc()) {
                     echo "Your username is incorrect, Re-enter CREDENTIALS";
            }
                 else {
                     $_SESSION['id'] = $id;
                     header('Location: Profile.php');
                }
        }