not really sure what you are saying,

sorry.

now: You can add custom attribute for a file. It can be type of text, checkbox, date/time ... or select.
Then you can enter manually options for select dropdown or let user enter it himself.

What I was wondering is:

is there a simple way to connect that select form with table data in database so options are populated automatically.
fe. you are uploading images of cars and as attribute select car manufacturer. That list can and will grow, so should file's custom attribute options

I hope my english was sufficient now. :)

Did you ever figure this out? I'm actually working on it now. What I need to do is add an attribute type that lets you select names from a list of all users.

Then on that the user's profile page, I can have a block that lists all the pages that have been "linked" to this user via that select attribute.

There's a basic tutorial here for creating a new attribute:

http://www.concrete5.org/documentation/how-tos/developers/create-a-...

This tutorial explains how to create a basic custom attribute, but I'm getting a little hung up somewhere around the db.xml step.

I'll let you know if I get anywhere...