How to develop for iphone application about "retrieving database file on web"?

I'm a newbie to iphone developer.

Well, currently, I'm developing iphone for Location Based Service.

That application need to have these functions. 1. hierarchical tree-view on navigation bar. 2. list up page 3. detail page

for example,

Let's say. I have top category like "Restaurant, Hotel, Gift Shop" Second level "New York, LA, London,....."

Third Level displays all Data with 1 photo. Fourth Level displays Detail of that "Restaurant or Hotel, Gift shop, ..."

So, My Only Interest is "How to retrieve the data from remote database server. not using iphone local one."

Because, that locations, and shops should be updated frequently, (you know some shops closed, new shops opens.)

So, till now, I figured out that using XML to retrieve data.

However, using XML is the most effective way to implement?

Is there any other way to accomplish this work?

You know, transferring XML data via 3G Network is really slow. XML file have more bytes than plist file.

I'm currently a beginner of iphone development.

So, please help me find a right way!!

And, one more question, if I use xml way. Is it开发者_运维技巧 possible to Paging? (First page 10 lists up, below that more button...)

well, you might guess each category have hundreds of shops!!

Why don't you start by learning some basics about the platform by working through the numerous tutorials and bountiful sample code available?

JSON will be more compact than XML generally.