Question

I am at a real loss.. For the past two weeks I have been working on fine tuning the way data is parsed, displayed and held in my app.

I have two view controllers, the first has four tables that when selected load a uitableview full of data that is parsed from an xml file. each xml file is different but have key fields that relate to each other. I need to speed up the way I display this data in the uitableview as when I do my second search when I check my ManufactureID against every single modle avalible to all manufactures.. it take a considrible amount of time to load.

I would like to do this behind the scenes before the view is even about to load and I have heard the best way to achieve this will be to use core data.. but I am not sure how to get this to work with the way I am doing things now.

If you have any examples, suggestions or anything that might help me I could seriously use someones input right about now as I am just abit stuck. For instance how do I get the data that are in my .xml files into the coredata? how to I create the relation ship ID’s? etc.

Answer 1

First off, is there any reason to keep the information in XML files? Everything will be a lot easier (and faster!) if you just move it all to a CoreData datastore from the start instead of parsing/preloading everything to an in-memory store at launch (or whatever).

As to how to model your relationships, you could always set your CoreData model to exactly match your XML data. So, say, one Entity per file and one Attribute per record in said file. There’s no reason you have to use CoreData Relationships to model the relationships in your XML. If you have IDs in the files already, just make an Attribute called xmlId or something and fetch based on that just like you were doing a SQL query. You’d miss out on a lot of automatic ORM-ness of CoreData, but if you’ve been dealing with XML this whole time, I doubt you’ll notice.

If you really want to set up the relationships between your CoreData-managed objects, you’ll have to somehow match up objects by their IDs in the XML either by importing the IDs into CoreData and then doing the math, or by somehow taking care of this when you parse. Hard to give any specific advice here without knowing more about how your data are modeled.

There’s some sample code that does half of what you want (it reads XML into a in-memory CoreData store, but doesn’t model any relationships). Check out TopSongs (http://developer.apple.com/library/ios/#samplecode/TopSongs)