update data from a master copy of the app

update data from a master copy of the app

I have a pretty strong background in C++ and am making the switch to
objective-c to try to make an iphone app. A main component of my app will
be a database that stores various information (less important but what
would you recommend to store class objects (array, linked list, etc...). I
have a few questions.
1) Is there a way to update the database of the app without requiring
users to update to a new version from the app store?
2) If there is, where & how do you pull the data into your app. Do you
have to pull it from a website?
2a) Is there a way to make a master copy of the app that I can make data
changes in and then have that copy update all other versions of the app?
All answers are greatly appreciated. Thank you.