Core Data İleri Seviye: Migration, Performance ve CloudKit Sync

1// Modern Core Data Stack
2class PersistenceController {
3    static let shared = PersistenceController()
4 
5    let container: NSPersistentContainer
6 
7    init(inMemory: Bool = false) {
8        container = NSPersistentContainer(name: "MyApp")
9 
10        if inMemory {
11            container.persistentStoreDescriptions.first?.url = URL(fileURLWithPath: "/dev/null")
12        }
13 
14        // WAL mode - concurrent read/write performansı
15        let description = container.persistentStoreDescriptions.first
16        description?.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
17        description?.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
18 
19        container.loadPersistentStores { description, error in
20            if let error = error as NSError? {
21                fatalError("Core Data error: \(error), \(error.userInfo)")
22            }
23        }
24 
25        container.viewContext.automaticallyMergesChangesFromParent = true
26        container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
27    }
28 
29    // Background context - ağır işlemler için
30    func newBackgroundContext() -> NSManagedObjectContext {
31        let context = container.newBackgroundContext()
32        context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
33        return context
34    }
35}

1// Lightweight Migration - otomatik (model mapping gerekli değil)
2// Desteklenen değişiklikler:
3// ✅ Yeni attribute/entity ekleme
4// ✅ Optional → Non-optional (default value ile)
5// ✅ Attribute yeniden adlandırma (Renaming ID ile)
6// ✅ Relationship ekleme
7 
8// Heavyweight Migration - manual mapping model gerekli
9// Gerekli durumlar:
10// ⚠️ Attribute tip değiştirme (String → Int)
11// ⚠️ Entity birleştirme/bölme
12// ⚠️ Karmaşık veri dönüşümleri
13 
14// Staged Migration (iOS 17+) - yeni API
15let container = NSPersistentContainer(name: "MyApp")
16let stages: [NSMigrationStage] = [
17    NSLightweightMigrationStage(["MyAppV1.mom", "MyAppV2.mom"]),
18    NSCustomMigrationStage(
19        migratingFrom: "MyAppV2",
20        to: "MyAppV3"
21    ) { context in
22        // Custom transformation logic
23        let request = NSFetchRequest<NSManagedObject>(entityName: "User")
24        let users = try context.fetch(request)
25        for user in users {
26            let fullName = "\(user.value(forKey: "firstName")!) \(user.value(forKey: "lastName")!)"
27            user.setValue(fullName, forKey: "displayName")
28        }
29        try context.save()
30    }
31]

1// Batch Insert - 10x hızlı
2func batchInsertProducts(_ products: [ProductDTO]) async throws {
3    let context = PersistenceController.shared.newBackgroundContext()
4    try await context.perform {
5        let batchInsert = NSBatchInsertRequest(
6            entity: CDProduct.entity(),
7            objects: products.map { product in
8                [
9                    "id": product.id,
10                    "name": product.name,
11                    "price": product.price,
12                    "updatedAt": Date()
13                ] as [String: Any]
14            }
15        )
16        batchInsert.resultType = .objectIDs
17        let result = try context.execute(batchInsert) as! NSBatchInsertResult
18        let objectIDs = result.result as! [NSManagedObjectID]
19 
20        // Main context'e bildir
21        NSManagedObjectContext.mergeChanges(
22            fromRemoteContextSave: [NSInsertedObjectsKey: objectIDs],
23            into: [PersistenceController.shared.container.viewContext]
24        )
25    }
26}
27 
28// Batch Update
29func markAllAsRead() async throws {
30    let context = PersistenceController.shared.newBackgroundContext()
31    try await context.perform {
32        let batchUpdate = NSBatchUpdateRequest(entityName: "Notification")
33        batchUpdate.predicate = NSPredicate(format: "isRead == NO")
34        batchUpdate.propertiesToUpdate = ["isRead": true, "readAt": Date()]
35        batchUpdate.resultType = .updatedObjectIDsResultType
36        try context.execute(batchUpdate)
37    }
38}
39 
40// Batch Delete
41func deleteOldLogs() async throws {
42    let context = PersistenceController.shared.newBackgroundContext()
43    try await context.perform {
44        let fetchRequest: NSFetchRequest<NSFetchRequestResult> = CDLog.fetchRequest()
45        fetchRequest.predicate = NSPredicate(format: "date < %@", Date().addingTimeInterval(-30*24*3600) as NSDate)
46        let batchDelete = NSBatchDeleteRequest(fetchRequest: fetchRequest)
47        batchDelete.resultType = .resultTypeObjectIDs
48        try context.execute(batchDelete)
49    }
50}

1// Optimized NSFRC
2class ProductListViewModel: NSObject, ObservableObject, NSFetchedResultsControllerDelegate {
3    @Published var products: [CDProduct] = []
4    private var frc: NSFetchedResultsController<CDProduct>!
5 
6    override init() {
7        super.init()
8        setupFRC()
9    }
10 
11    private func setupFRC() {
12        let request: NSFetchRequest<CDProduct> = CDProduct.fetchRequest()
13        request.sortDescriptors = [NSSortDescriptor(keyPath: \CDProduct.name, ascending: true)]
14        request.fetchBatchSize = 20 // ⚡ Lazy loading
15        request.relationshipKeyPathsForPrefetching = ["category"] // Prefetch
16 
17        frc = NSFetchedResultsController(
18            fetchRequest: request,
19            managedObjectContext: PersistenceController.shared.container.viewContext,
20            sectionNameKeyPath: "category.name",
21            cacheName: "products" // Disk cache
22        )
23        frc.delegate = self
24        try? frc.performFetch()
25        products = frc.fetchedObjects ?? []
26    }
27 
28    func controllerDidChangeContent(_ controller: NSFetchedResultsController<any NSFetchRequestResult>) {
29        products = frc.fetchedObjects ?? []
30    }
31}

1// NSPersistentCloudKitContainer - otomatik sync
2class CloudPersistenceController {
3    let container: NSPersistentCloudKitContainer
4 
5    init() {
6        container = NSPersistentCloudKitContainer(name: "MyApp")
7 
8        guard let description = container.persistentStoreDescriptions.first else { fatalError() }
9        description.cloudKitContainerOptions = NSPersistentCloudKitContainerOptions(
10            containerIdentifier: "iCloud.com.myapp"
11        )
12        description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
13        description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
14 
15        container.loadPersistentStores { _, error in
16            if let error { fatalError("CloudKit error: \(error)") }
17        }
18 
19        container.viewContext.automaticallyMergesChangesFromParent = true
20 
21        // Remote change notification
22        NotificationCenter.default.addObserver(
23            self,
24            selector: #selector(handleRemoteChange),
25            name: .NSPersistentStoreRemoteChange,
26            object: container.persistentStoreCoordinator
27        )
28    }
29 
30    @objc private func handleRemoteChange(_ notification: Notification) {
31        // CloudKit'ten yeni veri geldi
32    }
33}

1// ✅ Doğru: Background context ile ağır işlem
2func importLargeDataset(_ items: [DataItem]) async throws {
3    let context = PersistenceController.shared.newBackgroundContext()
4    try await context.perform {
5        for item in items {
6            let entity = CDItem(context: context)
7            entity.configure(with: item)
8        }
9        try context.save()
10    }
11}
12 
13// ❌ Yanlış: Main context'te ağır işlem
14func importOnMainThread(_ items: [DataItem]) {
15    let context = PersistenceController.shared.container.viewContext
16    // Bu UI'ı dondurur!
17    for item in items { /* ... */ }
18}

1// @FetchRequest ile SwiftUI entegrasyonu
2struct ProductListView: View {
3    @FetchRequest(
4        sortDescriptors: [SortDescriptor(\.name)],
5        predicate: NSPredicate(format: "isActive == YES"),
6        animation: .default
7    )
8    private var products: FetchedResults<CDProduct>
9 
10    var body: some View {
11        List(products) { product in
12            ProductRow(product: product)
13        }
14    }
15}
16 
17// SectionedFetchRequest (iOS 15+)
18struct GroupedProductsView: View {
19    @SectionedFetchRequest(
20        sectionIdentifier: \.category?.name,
21        sortDescriptors: [SortDescriptor(\.category?.name), SortDescriptor(\.name)]
22    )
23    private var sections: SectionedFetchResults<String?, CDProduct>
24 
25    var body: some View {
26        List {
27            ForEach(sections) { section in
28                Section(section.id ?? "Other") {
29                    ForEach(section) { product in
30                        Text(product.name ?? "")
31                    }
32                }
33            }
34        }
35    }
36}

1// Core Data entity'si
2// CDProduct.xcdatamodeld → Product entity
3 
4// SwiftData modeli (aynı store'u kullanabilir)
5@Model
6class Product {
7    var name: String
8    var price: Decimal
9    var isActive: Bool
10 
11    init(name: String, price: Decimal, isActive: Bool = true) {
12        self.name = name
13        self.price = price
14        self.isActive = isActive
15    }
16}
17 
18// Coexistence: her ikisini de kullan
19// Core Data: eski ekranlar
20// SwiftData: yeni özellikler