在设备上存储和更新数据的最佳方法

Question

Every time, when user launches application, app sends request to API and receive Data from it. I have to storage old data in a file on device and update them with every launch. When size of Data will be over than 3-5 mb, reading can be very long, isn't it?
My questions is: if i will store more than 5 mb of Data in file, can i quickly fetchs them, or only use database?
If yes, how can i create directory and put file to it?
And should i archive them?

Answer 1

I had a similar task and used CoreData with background fetch via DispatchQueue. I think this should help.

EDIT:

guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
        return
}
DispatchQueue.global(qos: .background).async {

    let managedContext = appDelegate.persistentContainer.viewContext
    let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "ENTITY")
    do {
        self."NSManagedObject ARRAY" = try managedContext.fetch(fetchRequest)
        } catch let error as NSError {
            print("Could not fetch. \(error), \(error.userInfo)")
          }
    DispatchQueue.main.async {
        //MAKING CHANGES TO VIEW
    }
}

PS I don't know how fast this fetch is, though it helped a lot in my task.