Save managedObjectContext partly

问题

I have 3 transaction already in NSManagedObjectContext: A, B, C. They were performed / added to context in the same order.

How can I save only the first A transaction, but keep unsaved B, C on context.

insert A, insert B, insert C, commit A, ..

Unfortunately NSManagedObjectContext can not do commit A, but save all the transactions.

回答1:

Maybe I missing something. Your goal is to save a specific object, say A, only and only if A's data has been committed to the server. Am I wrong?

If this is the case, you can take advantage of NSOperation class. Wrap your work (a save to the persistent store or a commit to the server) into an NSOperation subclass. Add a dependency between them.

Just an example.

let serverOperation : NSOperation = ...
let localOperation : NSOperation = ...
localOperation.addDependency(serverOperation)

let operationQueue = NSOperationQueue.mainQueue()
operationQueue.addOperations([serverOperation, localOperation], waitUntilFinished: false)

Another way could be that the save and commit operations are considered as a unique transaction.

Let me know if something it's not clear.

来源：https://stackoverflow.com/questions/30479793/save-managedobjectcontext-partly