in MainActor

https://github.com/quaternionboy/LifeKPIs-SwiftData-Data-Model/tree/Profiling-LifeKPIs-Tests

https://github.com/quaternionboy/LifeKPIs-SwiftData-Data-Model

https://github.com/quaternionboy/LifeKPIs-SwiftData-Data-Model

yes, works

workaround @Model final class Item { var name: String var id: UUID @Relationship(deleteRule:.cascade, inverse: \Entry.item) var entries: [Entry] init(name: String) { self.name = name self.id = UUID() entries = [] } } extension Item { private var _entries: [Entry]? { return try? self.context?.fetch(FetchDescriptor<Entry>(predicate:#Predicate<Entry>{ $0.item.id == id},sortBy: [SortDescriptor(\Entry.date, order: .forward)])) } } extension Item { func checkingDate()->Date?{ let _ = _entries //... return Date() } } But is really awkward not allowed directly to access the collection property inside one entity...

Making Item optional fixes the problem: var item: Item?