Swift 3 Core Data - How to save context synchronously?

Question

I need to import data into one enity, and then another entity that has a relationship with the first. The problem is that it crashes on the second entity because the the save is not complete on the first. How should I best deal with this in Swift 3 / Xcode 8 / IOS 10?

self.viewContext.save()  

I need to make sure the save is complete before importing the second entity.

Answer 1

我发现它是同步保存的，但我必须在每一行之后保存，否则它只是无法正常工作。