SQL Hidden Problem

[Brendan]

Right. This script just adds some information into a database. The information comes from text-boxes. My problem is that, when everything works until I hit the Submit button. The entries in the text-boxes disappear and nothing happens. I wrote a viewing script to check and see if the values were actually entered into the database, but no such luck. Any idea what I'm doing wrong?

<?php

if ($_POST['submit'])
{
  //connect to mysql
  $connect = mysql_connect('localhost','username','password');
  //verify connection
  if (!$connect)
  {
    echo 'Unable to connect to MySQL<br>' . mysql_error() . '';
  }

  //select a database
  $select = mysql_select_db('database');
  //verify db selection
  if (!$select)
  {
    echo 'Unable to select a database<br>' . mysql_error() . '';
  }

  //get values
  //to be inserted into database
  $title = $_POST["title"];
  $author = $_POST["author"];
  $message = $_POST["message"];
  $tdate = $_POST['tdate'];

  //add values into database
  //add them in the corresponding fields
  $query = "INSERT INTO news (id,title,author,message,tdate)" .  "VALUES ('NULL','$title','$author','$message','$tdate')";
  $r_query = mysql_query($query);
  //veryify query
  if ($r_query)
  {
    echo 'Query has been completed.';
  }
}
else
{
?>

<form method="post" action="sql_add.php">
<table>
 <tr>
  <td>Title:</td>
  <td><input type="text" name="title"></td>
 </tr>
 <tr>
  <td>Author:</td>
  <td><input type="text" name="author"></td>
 </tr>
 <tr>
  <td>Date:</td>
  <td><input type="text" name="tdate"></td>
 </tr>
 <tr>
  <td>Message:</td>
  <td><input type="text" name="message"></td>
 </tr>
 <tr>
  <td>&nbsp;</td>
  <td><input type="submit" name="submit"></td>
 </tr>
</table>
</form>

<?php
}
?>

Thanks ahead of time,
--Brendan