macOS NSArrayController and Core Data

I'm creating a Core Data application. When I import the database, the app copies the database file to the application support folder. Basically, it replaces the storedata file with a new one. The problem is that I need to reload the content. The changes are only taking effect after I restart. I would like to make the changes take effects without having to restart the app. How may I do that?

Thanks in advanced!