在查询中将会话用户名提交回数据库

Basically i want whoever creates a note on my website to be the "author" of that note.

So whoever is logged in when they create the note should be the author.

At the moment in login_form.php i have created a session which is the "included" in my general_notes.php. In general_notes.php i have the following code for when the user clicks to add a note:

<p class="fa fa-plus hover-cursor icon-spin noSelect" data-toggle="modal" data-target="#addGeneralNote" style="font-size: 16pt;"></p>

which runs:

<!-- Modal -->
<div id="addGeneralNote" class="modal fade" role="dialog">
  <div class="modal-dialog">

    <!-- Modal content-->
    <div class="modal-content">
      <div class="modal-header header-notes">
        <button type="button" class="close" data-dismiss="modal">&times;</button>
        <h4 class="modal-title">Add General Note</h4>
      </div>
      <!-- Form submission data -->
      <form action="addNewNote.php" method="POST">
          <div class="modal-body">
            <p>Please enter the note you wish to create.</p>
            <textarea id="addGeneralNoteName" placeholder="Enter a note name..." name="title" maxlength="100"></textarea>
            <textarea id="addGeneralNoteText" placeholder="Enter note here..." name="content"></textarea>
            <input type="checkbox" name="pinned"> Pin Note to your homepage
          </div>
          <div class="modal-footer footer-notes">
            <button type="submit" class="btn btn-success">Create</button>
          </div>
      </form>
    </div>

  </div>
</div>

You'll see in the form there is addNewNote.php which runs:

<?php

if (isset($_POST['title'], $_POST['content'], $_SESSION['username'])) 
{
    $title = $_POST['title'];
    $content = $_POST['content'];
    $author = $_SESSION['username'];

    $stmt = "INSERT INTO Notes (NoteName, Note, Author, DateCreated) VALUES (?, ?, ?, GETDATE())";
    $params = array($title, $content, $author);

    $stmt = sqlsrv_query($conn, $stmt, $params);

    if ($stmt === false) 
    {
        die( print_r(sqlsrv_errors(), true));
    }

    header('location: general_notes.php');
}

else
{
    echo "No Data";

}


?>

Before i added to the isset $_SESSION['username'] it ran fine.

At the moment it hits this part:

else
{
    echo "No Data";

}

of the isset function

So how how do i pass through the session username into my addNewNote.php script?