File structure in database - php

Question

I'm making a simple file listing function in PHP, just to recursively list all the files in a directory.
The function I have right now looks something like this:
<?php
function listFiles($dir){
echo "<ul class=\"filebrowser\">";
$dirCont = scandir($dir); // scan the whole directory
sortFoldersFirst($dirCont,$dir); // sort alphabetically, folders first
foreach ($dirCont as $value) {
if (!in_array($value,array(".","..",".deleted"))){ // don't list the parent folder, current folder, or the (hidden) .deleted folder
if (is_dir($dir . DIRECTORY_SEPARATOR . $value)){ // if it's a folder
echo "<h3 class=\"filebrowser\">" . $value . "</h3>"; // show the folder name
listFiles($dir . DIRECTORY_SEPARATOR . $value); // do the same again for the child folder
} else {
echo "<li>".$value."</li>"; // a link to the file
}
}
}
echo "</ul>";
}
?>
This gives me something like this:
This technique works just fine, however, I'd like to store a little more information about the files, like the author, comments, maybe a link to a thumbnail etc.
I'd like to get rid of the 'real' directory structure, and store everything in a database. (Just all files in 1 big folder, and links to the files in the database, not the actual files)
How can I store this information in the database, and how can I get it back out, without changing the result in the browser.
In other words: how can I get the tree structure in and out of the database, and how do I recursively loop through it.
I found this answer.
It shows how to make a database tree structure by saving the parent folder's id for every file/folder. This makes it easy to get the full path of a file, but it seems a bit less convenient to list all contents of a folder.
Is there a better solution to this problem?
Thanks in advance,
Pieter