CODEWITHSUNDEEP
iphoneipadcore-dataios
BeachRunnerFred
BeachRunnerFred

Reputation: 18578

Am I using Core Data properly by fetching an object once at startup and calling save when I want to persist the data?

I'm diving into iOS programming and am using Core Data in my app to persist the game data, however, I'm wondering if my approach is the wrong way to use Core Data. I have three tables in my DB, with the first two having a one-to-many relationship with the another table (i.e. UserProfile -->> Puzzle Packs -->> Puzzles).

The approach I'm taking to use and persist the data is simple, retrieve an instance of a UserProfile using a NSFetchedResultsController and store the UserProfile object as an instance var in my App Delegate. Then I use that UserProfile object throughout the rest of the code to access and modify the state of the puzzle packs and puzzles (representing the user's progress in the game) and whenever I make a change to the objects, I just call the NSManagedObjectContext's save method to update the DB, which is is also stored in the App Delegate.

My question is, should I be fetching data from the DB anytime I need to access or modify it or is my current approach, of fetching the top object once and calling the save method often, the correct way to use Core Data?

Thanks in advance for your wisdom! I apologize if my question is odd, I'm still a noob.

Upvotes: 4

Views: 200

Answers (1)

Joshua Nozzi
Joshua Nozzi

Reputation: 61248

As long as you're only ever working with these objects with a single NSManagedObjectContext (ie, you never have to merge changes between contexts) then I don't see a problem with fetching once, and saving as needed.

That said, the moment you work with multiple contexts (for example, using NSOperation/NSOperationQueue or other multi-threading techniques, which require separate contexts), you'll want to make sure you merge changes and update other contexts so changes from one thread don't clobber something on another.

Upvotes: 2

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