Realm vs Core Data Comparison

// Realm Swift — reactive data model
import RealmSwift

// Data model
class Task: Object, ObjectKeyIdentifiable {
    @Persisted(primaryKey: true) var id: ObjectId
    @Persisted var title: String = ""
    @Persisted var isCompleted: Bool = false
    @Persisted var createdAt: Date = Date()
}

// Reactive usage with SwiftUI
struct TaskListView: View {
    @ObservedResults(Task.self) var tasks

    var body: some View {
        List {
            ForEach(tasks) { task in
                TaskRow(task: task)
            }
        }
        .toolbar {
            ToolbarItem {
                Button("Add") {
                    $tasks.append(Task())
                }
            }
        }
    }
}

// Core Data + SwiftData — iOS 17+ modern approach
import SwiftData
import SwiftUI

// SwiftData model (with @Model macro)
@Model
class Task {
    var id: UUID
    var title: String
    var isCompleted: Bool
    var createdAt: Date

    init(title: String) {
        self.id = UUID()
        self.title = title
        self.isCompleted = false
        self.createdAt = Date()
    }
}

// Usage with SwiftUI
struct TaskListView: View {
    @Environment(\\.modelContext) private var context
    @Query(sort: \\.createdAt) var tasks: [Task]

    var body: some View {
        List(tasks) { task in
            Text(task.title)
                .strikethrough(task.isCompleted)
        }
    }

    func addTask() {
        let task = Task(title: "New task")
        context.insert(task)
    }
}