Core Data multi thread application

by

The Apple Concurrency with Core Data documentation is the place to start. Read it really carefully… I was bitten many times by my misunderstandings!

Basic rules are:

  1. Use one NSPersistentStoreCoordinator per program. You don’t need them per thread.
  2. Create one NSManagedObjectContext per thread.
  3. Never pass an NSManagedObject on a thread to the other thread.
  4. Instead, get the object IDs via -objectID and pass it to the other thread.

More rules:

  1. Make sure you save the object into the store before getting the object ID. Until saved, they’re temporary, and you can’t access them from another thread.
  2. And beware of the merge policies if you make changes to the managed objects from more than one thread.
  3. NSManagedObjectContext‘s -mergeChangesFromContextDidSaveNotification: is helpful.

But let me repeat, please read the document carefully! It’s really worth it!

More Related Contents:

  1. Any way to pre populate core data?
  2. The model used to open the store is incompatible with the one used to create the store
  3. iPhone Core Data “Automatic Lightweight Migration”
  4. Core Data and threads / Grand Central Dispatch
  5. How do I delete all objects from my persistent store in Core Data?
  6. How to get the indexpath.row when an element is activated?
  7. How can I programmatically get the MAC address of an iphone
  8. Detect if the device is iPhone X
  9. Pass data through segue
  10. Determine on iPhone if user has enabled push notifications
  11. Getting a list of files in a directory with a glob
  12. NSURLConnection and Basic HTTP Authentication in iOS
  13. Detect Retina Display
  14. Setting an image for a UIButton in code
  15. Core Data background context best practice
  16. iOS: Keep an app running like a service
  17. Testing CoreLocation on iPhone Simulator
  18. Remove gradient background from UIWebView?
  19. Saving image to Documents directory and retrieving for email attachment
  20. How to draw a “speech bubble” on an iPhone?
  21. detecting if iPhone is in a dark room
  22. Volunteermatch API Objective C
  23. How to set the full width of separator in UITableView
  24. “Your binary is not optimized for iPhone 5” (ITMS-90096) when submitting
  25. Open PDF file using swift
  26. What is the difference between UIApplication.sharedApplication.delegate.window and UIApplication.sharedApplication.keyWindow?
  27. How to get the front camera in Swift?
  28. Can’t connect IBOutlet in Interface Builder
  29. How do I calculate the UILabel height dynamically [duplicate]
  30. Two colors for UILabel TEXT

Leave a Comment