using coredata for storing / caching non standard data types

I'm rearching the best ways to store non standard types (string, int16 etc) on the iphone. What I will ultimately be doing is downloading an xml file and storing values such as date, title, name, mediaurl. I've just discovered the coredata data model and I believe it would开发者_开发问答 be a good candidate for storing such data so I don't have to download the xml the next time the app starts.

What I'm unsure of is the limitations (if any) of what I can store in a entity. For example one of the xml elements would hold a url to a small piece of audio (less than 1mb) and a url to an image. Would it be appropriate to store audio data , image as an attribute in an entity or should it be kept to strings and ints etc and the non standard types stored else where?

I guess what I'm really asking is, is the datamodel suitable for caching?

Ultimately what I'm seeking is a solution for storing data on the device in a location that is not tied to any one view, kinda an atomic model with everything I need that I can just dip into no matter view I'm in.

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The data model is suitable for caching, but because you don't have an explicit control of the cache (you can fault a data object but it may remain in the memory), it's recommended to separate very large binary objects. Store them as resources on the filesystem, and manage their links (URLs or paths) in Core Data.

< 1MB file seems okay to be handled by Core Data, but it also depends how many of them your application uses.

Also if you do store large files in Core Data, you should use SQLite storage.

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The above answer from MHC is good, but if you're storing large binary objects that don't need to be indexed (which can't be done in SQLite anyway), the recommended way is to store the actual data somewhere on the file system (say, in the NSDocumentsDirectory), and store path to the file inside the Core Data entity.

Core Data loads all parts of a fetched object into memory, which for a few instances of entities with binary data could quickly cause you to run out of memory on an iOS device.

If it's stored in the filesystem, you can lazy-load the data just when you need it.