What is the difference between using Realm and Core Data when implementing complex data migration processes?

Realm and Core Data are two popular data storage frameworks on iOS, but they differ in their migration approaches:

• Core Data uses a data model with versioning. When changing the schema, you need to create a new model version and define migrations, which can be automatic (for simple changes) or manual (for complex changes). Migrations in Core Data can be quite complex and require careful version management.

• Realm offers a simpler and more flexible migration mechanism. When changing the schema, you just need to increment the schema version and describe how to transform old objects into new ones within the migration block. Realm automatically handles most changes, and the developer only needs to specify logic for complex cases.

Thus, Realm is generally easier to implement for complex migrations thanks to its more intuitive API and automation, whereas Core Data requires more detailed version and migration scenario management.