{"id":48158,"date":"2025-06-19T15:38:38","date_gmt":"2025-06-19T19:38:38","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=48158"},"modified":"2026-01-20T18:03:26","modified_gmt":"2026-01-20T23:03:26","slug":"swiftdata-and-core-data-at-wwdc25","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2025\/06\/19\/swiftdata-and-core-data-at-wwdc25\/","title":{"rendered":"SwiftData and Core Data at WWDC25"},"content":{"rendered":"

SwiftData: Dive into inheritance and schema migration<\/a>:<\/p>\n

Discover how to use class inheritance to model your data. Learn how to optimize queries and seamlessly migrate your app’s data to use inheritance. Explore subclassing for building model graphs, crafting efficient fetches and queries, and implementing robust schema migrations. Understand how to use Observable<\/code> and persistent history for efficient change tracking.<\/p><\/blockquote>\n\n

I’m glad to see that inheritance isn’t on the chopping block, as some feared, but otherwise this was disappointing. For the second year in a row, there don’t seem to be any new features for Core Data (not even a mention in the session) or for integrating Core Data and SwiftData. Is Core Data frozen in time or still getting maintenance? How are you supposed to migrate when the feature sets—and even IDs—aren’t equivalent? Aren’t there tons of apps built on Core Data? What are they supposed to do? It seems like Apple doesn’t care.<\/p>\n\n

Fatbobman<\/a>:<\/p>\n

\n

SwiftData added only one feature this year—model inheritance—which isn’t widely used by most developers. Other highly requested capabilities, such as additional sync options (shared, public) and dynamic predicate adjustments, didn’t materialize in this release. That said, this update isn’t a failure. By fixing several critical bugs from previous versions and filling in some long-overdue functionality, SwiftData in Xcode 26 has become increasingly viable for real-world apps.<\/p>\n<\/blockquote>\n\n

Previously:<\/p>\n