validate.php

<?php
include 'dbconnection.php';
/**
 * Created by PhpStorm.
 * User: julian
 * Date: 06.11.16
 * Time: 22:38
 */
//Login
if($_POST['username']){
$uid= $_POST['username'];
$pwd = $_POST['password'];


$sql = "SELECT * FROM registration WHERE username='$uid' AND password = '$pwd'";
$result = $conn->query($sql);

if(!$row = mysqli_fetch_assoc($result)){
    header('Location: error.php');

}
else{
    $_SESSION['id'] = $row['id']; //ID FROM DATABASE für SESSION
    $_SESSION['username'] = $row['username']; //Username from Database für session

    header('Location: home.php');
}
}