Versioning Your SwiftData Schema
We started with a simple model. Then we added a new property and transformed existing data. Then we introduced a uniqueness constraint and cleaned up duplicates before enforcing it. Each change felt small in isolation. But every one of those changes altered the structure of data already stored on disk.
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SwiftData gives you the tools to do this properly. VersionedSchema gives you structure. SchemaMigrationPlan gives you control. Custom migration stages let you reshape data intentionally instead of hoping automatic migration handles everything.
It seems like they got this part of the SwiftData API right.
Previously:
