Using SwiftData with CloudKit

These rules only apply if the project is configured to use SwiftData with CloudKit.

• Never use @Attribute(.unique) or #Unique; they are not supported in CloudKit, and when used will cause local data to fail too.
• All model properties must always either have default values or be marked as optional.
• All relationships must be marked optional.
• Indexes and subclasses are supported in CloudKit, as long as the correct OS release is used.

Keep in mind that CloudKit is designed for eventual consistency – any SwiftData code written with CloudKit support must be able to function if data has yet to synchronize.