Should I create a second persistent store for this library in my app?

[bcye]

Hello,

I have the following code:

class CoreDataStack {

    var smStore: SMStore?
    
    lazy var managedObjectContext: NSManagedObjectContext = {
        let container = self.persistentContainer
        return container.viewContext
    }()

    private lazy var persistentContainer: NSPersistentContainer = {
        let container = NSPersistentContainer(name: "WHIR")
        container.loadPersistentStores { (_, error) in
            if let error = error as NSError? {
                // TODO: Find way to alert the user from here
                print(error)
            }
        }
        return container
    }()
    
    lazy var cloudPersistentContainer: NSPersistentContainer = {
        SMStore.registerStoreClass()
        let container = NSPersistentContainer(name: "WHIRCloud")
        let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
        
        if let applicationDocumentsDirectory = urls.last {
            let url = applicationDocumentsDirectory.appendingPathComponent("SingleViewCoreData.sqlite")
            let storeDescription = NSPersistentStoreDescription(url: url)
            storeDescription.type = SMStore.type
            container.persistentStoreDescriptions=[storeDescription]
            container.loadPersistentStores(completionHandler: { (storeDescription, error) in
                if let error = error as NSError? {
                    // Replace this implementation with code to handle the error appropriately.
                    // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                    
                    /*
                     Typical reasons for an error here include:
                     * The parent directory does not exist, cannot be created, or disallows writing.
                     * The persistent store is not accessible, due to permissions or data protection when the device is locked.
                     * The device is out of space.
                     * The store could not be migrated to the current model version.
                     Check the error message to determine what the actual problem was.
                     */
                    fatalError("Unresolved error \(error), \(error.userInfo)")
                }
            })
            return container
        }
        
        fatalError("Unable to access documents directory")
        
    }()
}

First, can I use to different stores or how would I go about this?
Second in the line let url = applicationDocumentsDirectory.appendingPathComponent("SingleViewCoreData.sqlite"), do I need to replace SingleViewCoreData.sqlite with something else? If so, what do I need to replace it with?

[paulw11]

Generally the idea of Seam3 is that CloudKit is hidden from your app as much as possible and you just use Core Data as normal. So, you wouldn't typically create a second persistent store, except in the case where you have an existing app that uses local-only core data and you want to migrate it to Seam3; Then you do need to create a second persistent store and migrate the existing data to it.

[bcye]

So I can't integrate it into the existing persistent store that I'm using with my app now? How could I migrate the data and would that be a one-time operation, because I've also read something about persistent store coordinator. Would that be a solution?

[bcye]

I mean basically, the code is run every app startup, so couldn't I just add the seam code to my persistent store?

Sorry, I haven't looked into core data in a while and don't know exactly how everything works.

[paulw11]

#59 offers advice on migrating to a new persistent store; This would be a one-time operation. Essentially you need to migrate your existing sqlite store to a Seam store.

[bcye]

Thank you.