facebook graph information and connecting with my server side data

[Tony]

Im trying to make an iphone app that will provide the user with data
on their facebook friends using the same app that is stored on my
server. What would be the ebst way to make the connections between
facebook friends and the user profiles on my server? Should I store
their facebook IDs on my server and use the facebook graph api to
check everyone else in the database so see if they are friends, and if
so, make a connection between them? Or is there a simpler cleaner way
to do this? Because this way I would have oto be doing periodic friend
checks and it wouldnt ever be real time. I dont think I was as clear
as I could ahve been but hopefully you guys get the gist of my problem