PHP Form adding NULL rows to my SQL database when making user account

Question

I'm creating a user registration form for my website in PHP and 'POST' the user data to my SQL database. When I made my first two users it posted the user info to my database such as username and email ALONG with a row of NULL for each field. I didn't change anything in my PHP code but now when I go to create a user it adds a new row to the database but all the fields are NULL, and a hash code for password. I don't know why its coming up as NULL. Below I will include my register.php code.

    <?php
#session_start();
#if(isset($_SESSION['User']))
#{
# header("Location: home.php");
#}
include_once 'dbconnect.php';

#if(isset($_POST['submit']))
#
     $uname = $_POST['uname'];
     $email = $_POST['email'];
     $upass = $_POST['upass'];

     $stmt = $dbh->prepare("SELECT COUNT(*) as `emailcount` FROM `User` WHERE email=:email");
     $stmt->execute(array("email" => $_POST['email']));
     $row = $stmt->fetch(PDO::FETCH_ASSOC);

     if ($row['emailcount'] > 0) {
        echo "<script>alert('Email $email already exists in our system. Please try another email')</script>";
     } else {


        $stmt = $dbh->prepare("INSERT INTO User(`uname`, `email`, `upass`) VALUES (:uname, :email, :upass)");

        $stmt->execute(array("uname" => $_POST['uname'], "email" => $_POST['email'], "upass" => md5($_POST['upass'])));
     }


?>

I will also include my HTML form that we are working with here

            <form method='post' action='register.php'>
                <pre>
                <div>
            <label>Name : (letters only)*</label>
<input type="text" name="uname" pattern="[A-Za-z]+" title="only letters" required />
</div>

<div>
<label>E-mail : (xyz@zyx.com)*</label>
<input type="email" name="email" pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}$" title="xyz@something.com" required />
</div>


<div>
<label>password : (at least 6 chars)</label>
<input type="password" name="upass" pattern=".{6,}" title="Six or more characters" required />
</div>



<input type='submit' name='submit' value='Sign Up'>
</pre>
</form>

Answer 1

Are you ever visiting register.php without a post submit? Because if you were to go to that page without doing a submit, the insert will still execute, but your variables will all be null since they are only set when $_POST['submit'] is set.

If that is the case, try this instead:

if(isset($_POST['submit']))
{
     $uname = $_POST['uname'];
     $email = $_POST['email'];
     $upass = $_POST['upass'];

     $stmt = $dbh->prepare("SELECT COUNT(*) as `emailcount` FROM `User` WHERE email=:email");
     $stmt->execute(array("email" => $_POST['email']));
     $row = $stmt->fetch(PDO::FETCH_ASSOC);

     if ($row['emailcount'] > 0) {
        echo "<script>alert('Email $email already exists in our system. Please try another email')</script>";
     } else {


        $stmt = $dbh->prepare("INSERT INTO User(`uname`, `email`, `upass`) VALUES (:uname, :email, :upass)");

        $stmt->execute(array("uname" => $_POST['uname'], "email" => $_POST['email'], "upass" => md5($_POST['upass'])));
     }
}