It depends whether your DB is online or offline.
If the DB is offline, you can retireve the binary file and save it with the proper extension to your HD.
If the file is online, you should use a file format which supports Streaming (I'm not an expert, you can Google for it) and take packages, but I'm not sure it will work.
A second solution can be saving the file to your remove server and then stream it.
Look here (
http://www.experts-exchange.com/Programming/Languages/Scripting/PHP/Q_21328203.html[
^])
Hope this helped.
LG