Does swift data supports deduplication with iCloud sync?
Asked on 03/29/2025
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Yes, Swift Data supports deduplication with iCloud sync through the use of a new schema macro that allows you to construct a compound constraint on persistent models. You can use the unique macro to specify which combinations of your model's properties must remain unique. When two model instances share the same unique values, Swift Data will perform an upsert on collision with an existing model, effectively avoiding duplicates. This feature is part of the enhancements introduced in Swift Data, as discussed in the session What’s new in SwiftData.
Track model changes with SwiftData history
Reveal the history of your model’s changes with SwiftData! Use the history API to understand when data store changes occurred, and learn how to use this information to build features like remote server sync and out-of-process change handing in your app. We’ll also cover how you can build support for the history API into a custom data store.
Platforms State of the Union
Discover the newest advancements on Apple platforms.
What’s new in SwiftData
SwiftData makes it easy to add persistence to your app with its expressive, declarative API. Learn about refinements to SwiftData, including compound uniqueness constraints, faster queries with #Index, queries in Xcode previews, and rich predicate expressions. Join us to explore how you can use all of these features to express richer models and improve performance in your app. To discover how to build a custom data store or use the history API in SwiftData, watch “Create a custom data store with SwiftData” and “Track model changes with SwiftData history”.