Can you store facebook users' data and for how long?

Hi I am developing a facebook app that involves the use of the user's email and ID. Storing users’ info to database is a more efficient approach for the purpose of the app. I am wondering if I am allowed to do this. I have read that facebook does not allow the storage of any kind of user's data for more than 7 days, however officially facebook开发者_如何学JAVA website does not seem to mention this. Do you have any information about this issue?

The official policies are here. One relevant paragraph is:

"You may cache data you receive through use of the Facebook API in order to improve your application’s user experience, but you should try to keep the data up to date. This permission does not give you any rights to such data."