Client Server with IPad

I have a bit of a design question if anyone at there cares to offer some advice (or point me in the right direction).

I am writing an IPad app that will be gathering data from a server and then will be using that data for some time (read: it would be nice to be able to store the data locally even when the app is not running). Anyone know of the best way to accomplish a feat like this.

Essentially, order of events would preferbly go something likes this:

1. User launches app.
2. IPad requests data from server.
3. Server supplies data.
4. User interacts with app etc.
5. User closes app.
6. At a later time, user launches app again.
7. App checks data, sees it is still up to date开发者_JAVA百科, reads in previous data from disk.
8. User interacts with data etc.

Thanks in advance.

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When the application is launching for the first time you should get all the data and store in to a local database.

When the user open the application after some other time just write make a webservice call that check for the last updated time, if it matches your time then leave it,else update the database.