Realm with SwiftUI: A Comprehensive Guide with Real-World Examples, CRUD Operations & Relationships

 

Realm is a powerful and efficient mobile database solution that works seamlessly with SwiftUI. It offers live objects, thread safety, automatic change tracking, and more — making it a great alternative to Core Data for local data persistence.

In this guide, we’ll walk through how to integrate Realm with SwiftUI, perform full CRUD operations, run complex queries, and handle relationships in a real-world-style example.

📦 Why Realm?

• Fast and lightweight
• Easy to use with SwiftUI
• Live data updates via ObservedResults
• Thread-safe
• Schema migrations made easy

🚀 Getting Started with Realm in SwiftUI

🔧 Step 1: Add Realm to Your Project

Use Swift Package Manager and add:

https://github.com/realm/realm-swift.git

Select the latest version.

🧱 Step 2: Define Your Realm Models

Let’s build a Task Management App with Projects and Tasks.

import RealmSwift

class Project: Object, ObjectKeyIdentifiable {
    @Persisted(primaryKey: true) var id: ObjectId
    @Persisted var title: String = ""
    @Persisted var tasks = RealmSwift.List<Task>()
}
class Task: Object, ObjectKeyIdentifiable {
    @Persisted(primaryKey: true) var id: ObjectId
    @Persisted var name: String = ""
    @Persisted var isCompleted: Bool = false
}

🧩 Setting Up the Realm Configuration

class RealmManager: ObservableObject {
    private(set) var realm: Realm?

init() {
        do {
            realm = try Realm()
        } catch {
            print("Failed to open Realm: \(error.localizedDescription)")
        }
    }
}

🧑‍🎨 SwiftUI View with Realm Integration

📃 Display a List of Projects

import RealmSwift

struct ProjectListView: View {
    @ObservedResults(Project.self) var projects
    var body: some View {
        NavigationView {
            List {
                ForEach(projects) { project in
                    NavigationLink(destination: TaskListView(project: project)) {
                        Text(project.title)
                    }
                }
                .onDelete(perform: $projects.remove)
            }
            .navigationTitle("Projects")
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Add") {
                        $projects.append(Project(value: ["title": "New Project"]))
                    }
                }
            }
        }
    }
}

🔄 CRUD Operations in Realm with SwiftUI

✅ Create a Task

func addTask(to project: Project, name: String) {
    guard let realm = project.realm else { return }
    try? realm.write {
        let newTask = Task()
        newTask.name = name
        project.tasks.append(newTask)
    }
}

✏️ Update a Task

func toggleCompletion(task: Task) {
    guard let realm = task.realm else { return }
    try? realm.write {
        task.isCompleted.toggle()
    }
}

❌ Delete a Task

func deleteTask(project: Project, indexSet: IndexSet) {
    guard let realm = project.realm else { return }
    try? realm.write {
        project.tasks.remove(atOffsets: indexSet)
    }
}

🔍 Complex Queries in Realm

// All completed tasks across all projects
let completedTasks = realm.objects(Task.self).where { $0.isCompleted == true }

// Projects with more than 3 tasks
let activeProjects = realm.objects(Project.self).where { $0.tasks.count > 3 }

🔗 Handling Relationships in Realm

In our example:

• A Project has many Tasks (one-to-many).
• Realm’s List<T> handles this relationship natively.

To access all tasks under a project:

let tasks = project.tasks

You can filter or sort them:

let sortedTasks = project.tasks.sorted(byKeyPath: "name")

🎨 TaskListView (Child Relationship Example)

struct TaskListView: View {
    @ObservedRealmObject var project: Project
    @State private var taskName = ""

var body: some View {
        VStack {
            List {
                ForEach(project.tasks) { task in
                    HStack {
                        Text(task.name)
                        Spacer()
                        Button(action: {
                            toggleCompletion(task: task)
                        }) {
                            Image(systemName: task.isCompleted ? "checkmark.circle.fill" : "circle")
                        }
                    }
                }
                .onDelete(perform: delete)
            }
            HStack {
                TextField("New Task", text: $taskName)
                Button("Add") {
                    addTask(to: project, name: taskName)
                    taskName = ""
                }
            }
            .padding()
        }
        .navigationTitle(project.title)
    }
    func delete(at offsets: IndexSet) {
        deleteTask(project: project, indexSet: offsets)
    }
}

🧪 Testing & Debugging Tips

• Use Realm.Configuration.inMemoryIdentifier for testing
• Add breakpoints inside try realm.write blocks
• Use Realm Studio to inspect your database visually

✨ Final Thoughts

Realm + SwiftUI is a powerful combo for building responsive, data-driven iOS apps. You get:

• Real-time UI updates
• Simple relationship management
• Easy schema migrations

Start small — then scale your models and views. With Realm’s speed and SwiftUI’s declarative syntax, your next app is in great shape!