Essentially, a user will click a star that is associated with a number in a predefined text field, the number will be passed to a php page, the php page will update a database,
You won't be able to do this with an InDesign generated SWF. The only way to make a connection to a database from Flash is via a combination of Actionscript connecting to AMF Zend PHP, which writes to the database.
You would have to write the ActionScript code that connects to the AMF PHP in an FLA and compile the SWF from Flash or FlashBuilder.
With that being said, there is no post data that can be passed from a SWF to a html and/or php page?
That's right, any button inside of an exported SWF would need a NetConnection object to communicate out to a sever side PHP script and a Responder object to get back results. I think the only option from InDesign would be to export an FLA and do the coding on the FLA's timeline, which would require some advanced ActionScript knowledge.