//Welcome.php

<?php
    require_once('lib/database.php');
    $data = new Database();
    $data->sql = "SELECT * FROM users ORDER BY uid";
    echo "<pre>";
    print_r($data->fetch_assoc());



/////////////////////////////////////////////////////////////////////////////////////////////

//login.php

<?php

ob_start();
require_once('lib/user.php');
?>
<?php
            $user = new User();

            $validate = $user->validate_login($_POST['username'], $_POST['password']);

            echo $validate;

            if($validate){

                header("Location: welcome.php");


            } else {

                header("Location: index.php");

            }
?>

<?php ob_flush(); ?>

/////////////////////////////////////////////////////////////////////////////////////////////

//signup.php

<?php

    include_once('lib/user.php');
    include_once('lib/database.php');


    $user = new User();

    $user->insert($_POST['username'], $_POST['password'], $_POST['email_address']);
    echo "saved";

/////////////////////////////////////////////////////////////////////////////////////////////

//Database.php

<?php

class Database{

    public function __construct(){
        $dbHost = "localhost";
        $dbUser = "root";
        $dbPass = "";
        $dbName = "portal";
        $this->conn = mysql_connect("$dbHost", "$dbUser", "$dbPass") or die(mysql_error());
        $mydb = mysql_select_db("$dbName") or die(mysql_error());
        return $this->conn;
    }

    public function execute(){

        $query = $this->sql;
        $this->result = mysql_query($query);

    }

    public function fetch_array(){

        $this->execute();

        while($fetch = mysql_fetch_array($this->result)){

            return $fetch;

        }

    }

    public function fetch_row(){

        $this->execute();

        while($fetch = mysql_fetch_row($this->result)){

            return $fetch;

        }

    }

    public function fetch_assoc(){

        $this->execute();

        while($fetch = mysql_fetch_assoc($this->result)){

            return $fetch;

        }

    }

    public function listall(){

        $this->execute();

        while($fetch = mysql_fetch_assoc($this->result)){

            return $fetch;

        }

    }

}


////////////////////////////////////////////////////////////////////////////////////////////

//user.php

<?php require_once('database.php'); ?>

<?php

class User extends Database{

    public function validate_login($username, $password){

        $sql = "SELECT username, password FROM users WHERE username='". $username ."' AND password='". $password . "'";
        $result = mysql_query($sql);

        if(mysql_num_rows($result) == 1) {

            return TRUE;
        }
            return FALSE;
    }

    public function insert($username, $password, $email_address){

        $sql = "INSERT INTO users(username, password, email_address) VALUES('$username','$password','$email_address')";
        $result = mysql_query($sql) or die(mysql_error());

        if($result){

            return TRUE;

        } else {

            return FALSE;

        }

    }
}

//////////////////////////////////////////////////////////////////////////////////////////////