NSFetchRequest returns old data even though the database is updated

问题

I'm working on a Multi-threaded application that uses Coredata.

When i save some data on one thread it goes to the database but when I try to fetch it from a different thread once the data is saved to the database, the fetch request returns the old data.

Any suggestions on how to fix this?

回答1:

This was an issue due to the MOC merge policy. I have used NSMergeByPropertyObjectTrumpMergePolicy earlier and switching to NSMergeByPropertyStoreTrumpMergePolicy fixed the issue. Keep in mind, this should be picked according to your need.

来源：https://stackoverflow.com/questions/22456959/nsfetchrequest-returns-old-data-even-though-the-database-is-updated