swiftdata-inheritance

SwiftData class inheritance requires annotating both your base class and subclasses with @Model, ensuring proper super.init() calls in subclass initializers to enable polymorphic relationships and type-based querying across shared base properties.

SwiftData inheritance suits hierarchical models needing shared base properties and type-based queries. Choose enums or protocols when your data represents distinct variants without shared state, or when you want to minimize migration risk during schema evolution by keeping model hierarchies shallow.

Type-based queries in SwiftData allow deep and shallow fetches across subclass hierarchies. You can fetch all subtypes using the base class or target specific subtypes, enabling polymorphic data retrieval across your inherited model structures.

SwiftData model inheritance migration risks increase with deeper hierarchies. Keep hierarchies shallow to minimize schema evolution pitfalls, and carefully plan migration strategies when modifying base or subclass properties to ensure polymorphic relationships remain intact.

Polymorphic relationships in SwiftData inheritance connect different subtypes through shared base classes. By annotating base and subclasses with @Model, you can model relationships that reference any subtype instance while maintaining type-based query capabilities.