iOS: How can I create a backup copy of my core data base? And how to export/import that copy?

Question

I want to offer the users of my app the possibility to create a backup of the core data database, especially in case he switches to a new device etc.

How would I do that

Answer 1

I created the following method with the help of Apple sample code. This will take a backup of core data files and place it to the path that you want.

Swift 5

/// Backing up store type to a new and unique location
/// The method is illustrated in the following code fragment, which shows how you can use migratePersistentStore to take a back up of a store and save it from one location to another.
/// If the old store type is XML, the example also converts the store to SQLite.
/// - Parameters:
///   - path: Where you want the backup to be done, please create a new unique directory with timestamp or the guid
///   - completion: Passes error in case of error or pass nil in case of success
class func backUpCoreDataFiles(path : URL, completion : @escaping (_ error : String?) -> ())
{

    // Every time new container is a must as migratePersistentStore method will loose the reference to the container on migration
    let container = NSPersistentContainer(name : "")
    container.loadPersistentStores
        { (storeDescription, error) in
            if let error = error
            {
                fatalError("Failed to load store: \(error)")
            }
    }
    let coordinator = container.persistentStoreCoordinator
    let store = coordinator.persistentStores[0]
    do
    {
        try coordinator.migratePersistentStore(store, to : path, options : nil, withType : NSSQLiteStoreType)
        completion(nil)
    }
    catch
    {
        completion("\(Errors.coredataBackupError)\(error.localizedDescription)")
    }
}