Question 1

How to handle migrations in Realm Swift?

Accepted Answer

Realm provides a migration block in Realm.Configuration where you increment the schema version and define changes manually. This can be error-prone for complex schemas, requiring careful testing to avoid data loss.

Question 2

Realm vs Core Data for iOS apps?

Accepted Answer

Realm offers a simpler, object-oriented API with better performance for reactive apps, while Core Data has deeper Apple ecosystem integration and mature tooling. Choose Realm for ease of use; Core Data for advanced features like iCloud sync.

Question 3

Can Realm databases sync between iOS and Android?

Accepted Answer

Yes, but it requires using Realm SDKs on both platforms and MongoDB Realm Sync for cloud synchronization. Data models must be compatible, and setup involves additional configuration for cross-platform consistency.

Question 4

How to encrypt a Realm database in Swift?

Accepted Answer

Generate a random key using SecRandomCopyBytes and add it to Realm.Configuration, as shown in the README example. This encrypts data at-rest, but key management must be handled securely to prevent data loss.

Question 5

Does Realm work with Combine framework?

Accepted Answer

Realm's live objects can be adapted to Combine using publishers, but native integration is limited compared to SwiftUI. You might need custom wrappers to fully leverage Combine's reactive streams with Realm data.

Question 6

How to perform background writes in Realm Swift?

Accepted Answer

Use write transactions within a background DispatchQueue, but ensure thread confinement as Realm objects are thread-bound. Misuse can lead to crashes, so follow Realm's threading guidelines carefully.

Realm

What is Realm?

Overview

Use Cases

Best For

Found a gem we're missing?

Not Ideal For

Pros & Cons

Pros

Cons

Open Source Alternative To

Frequently Asked Questions