Get Value of uID from Query and Output Session uID Upon Login
<?php
session_start();

require_once('../inc/db/dbc.php');
?>

<?php
    if($_SESSION['valid'] == 1){ #user has logged in by creating a session var
        echo "<a href='logout.php'>Logout</a>";
    }
    else{
        echo "<a href='index.php'>Login</a>";
    }
?>

<?php
session_start(); #recall session from index.php where user logged

require_once('../inc/db/dbc.php');

$connect = mysql_connect($h, $u, $p) or die ("Can't Connect to Database.");
mysql_select_db($db);

$LoginUserName = $_POST['userName'];
$LoginPassword = mysql_real_escape_string($_POST['userPass']);
//connect to the database here
$LoginUserName = mysql_real_escape_string($LoginUserName);
$query = "SELECT uID, uUPass, dynamSalt, uUserType FROM User WHERE uUName = '$LoginUserName';";

$result = mysql_query($query);
if(mysql_num_rows($result) < 1) //no such USER exists
{
    echo "Invalid Username and/or Password";
}
$ifUserExists = mysql_fetch_array($result, MYSQL_ASSOC);

function isLoggedIn()
{
    if(isset($_SESSION['valid']) && $_SESSION['valid'])
        header( 'Location: buyer/' ); # return true if sessions are made and login creds are valid
    echo "Invalid Username and/or Password";
    return true;
}

function validateUser() {
    $_SESSION['valid'] = 1;
    $_SESSION['uID'] = (isset($ifUserExists['uID'])) ? $ifUserExists['uID'] : null;
    $_SESSION['uUserType'] = 1; // 1 for buyer - 2 for merchant
}

$dynamSalt = $ifUserExists['dynamSalt'];  #get value of dynamSalt in query above
$SaltyPass = hash('sha512',$dynamSalt.$LoginPassword); #recreate originally created dynamic, unique pass

if($SaltyPass != $ifUserExists['uUPass']) # incorrect PASS
{
    echo "Invalid Username and/or Password";
}

else {
validateUser();
}
// If User *has not* logged in yet, keep on /login
if(!isLoggedIn())
{
    header('Location: index.php');
    die();
}
?>

<?php
session_start();
if($_SESSION['uUserType'] != 1) // error
{

    die("
    <div class='container_infinity'>
        <div class='container_full' style='position:static;'>
        <img src='img/error/noAccess.png' style='float:left;' /> <br />
        <h2>403 Error: You may not view this page. Access denied.</h2>
        </div>
    </div>
    ");
}

function isLoggedIn()
{
    return ($_SESSION['valid'] == 1 && $_SESSION['uUserType'] == 1);
}

//if the user has not logged in
if(!isLoggedIn())
{
    header('Location: ../index.php');
    die();
}
?>

<?php
    if($_SESSION['valid'] == 1 && $_SESSION['uUserType'] == 1){
        #echo "<a href='../logout.php'>Logout</a>";
        echo 'buyerid: '.$_SESSION['uID'];
        require_once('buyer_profile.php');
    }
    else{
        echo "<a href='../index.php'>Login</a>";
    }
?>