iOS app: Pre-populated large database not allowed - alternatives?

Question

So my iOS app has just been rejected because it's storing too much non-user-created data in the SQLite database, which lives in the Documents folder.

The app basically involves a relatively large library of images -- around 60-or-so megabytes of them to start, and there are also in-app purchases which each add an additional 60-or-so mb of images. Furthermore, the user can add their own images to the library.

Right now everything (images and all) is stored in an SQLite database, which is generated when the app is first launched. As the user adds more images, or purchases image packs, those images are added to the database. To the user, all the images (user-generated or not) behave the same in the app.

But Apple won't allow this: I can't have all that data stored in the SQLite database in the Documents folder unless I set it specifically NOT to back up to iCloud, as it's all recreatable data.

But if I set it to not back up, then the user-generated data won't back up either, which I definitely don't want.

Any suggestions how I might "split up" the database, such that all the user-generated stuff can be backed up, but the included-or-purchased stuff isn't?

Answer 1

The reason you are being rejected is not following the Data Storage Guidelines. Data created or edited by the user belongs within NSDocumentsDirectory, while application data should be stored elsewhere (i.e., the Application Support directory). These requirements are a result of how iCloud backup and disk space purging work on iOS.

For a Core Data application, this means your persistent stores must be split into two different sets of files, in two different locations. This, in turn, ends up driving much of the application architecture and data model. To have relationships between the user data and application data, for instance, you must use two different managed object model configurations and the relationship must be a fetched property.

There is more detail on how to implement this in this answer.

An alternative for your specific case would be to save the images on the file system, in the caches directory or elsewhere. User images could exist in NSDocumentsDirectory while application images could exist in NSCachesDirectory. This would remove the images from Core Data and instead your model objects would have the path to the image on the file system. This would be a short term fix to get you through submission, and would probably work.

Answer 2

One option will be, storing your data to a server and calling is using web service. During first launch. Or as per requirement.