Adding and editing persistent data in your app

At a glance

Project structure

Source bundle/
└── SwiftDataAnimals/
    ├── SwiftDataAnimalsApp.swift
    ├── Views/
    │   ├── AnimalListView.swift
    │   ├── AnimalCategoryListView.swift
    │   ├── AnimalDetailView.swift
    │   ├── ContentView.swift
    │   ├── ThreeColumnContentView.swift
    │   └── AnimalEditor.swift
    ├── Models/
    │   ├── Animal.swift
    │   ├── AnimalCategory.swift
    │   └── NavigationContext.swift
    └── PreviewHelper/
        ├── ModelContainerPreview.swift
        └── Preview+ModelContainer.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 3 project/configuration file(s) and 16 source declaration(s).

Overall architecture

flowchart LR
    N1["SwiftDataAnimalsApp"]
    N2["ContentView"]
    N3["SwiftData APIs"]
    N1 --> N2
    N2 --> N3

Reference code

SwiftDataAnimals/SwiftDataAnimalsApp.swift:11 — architecture anchor

@main
struct SwiftDataAnimalsApp: App {
    // ...
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into SwiftData.

Ownership and state

classDiagram
    AnimalListView *-- String : animalCategoryName
    AnimalList *-- String : animalCategoryName
    AnimalList *-- Array : animals
    AddAnimalButton o-- Bool : isActive

Ownership evidence

SwiftDataAnimals/Views/AnimalListView.swift:12 — stored dependency or nearest verified ownership anchor

struct AnimalListView: View {
    let animalCategoryName: String?
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

SwiftDataAnimals/SwiftDataAnimalsApp.swift:12 — representative type boundary

struct SwiftDataAnimalsApp: App {
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

SwiftDataAnimals/Views/AnimalCategoryListView.swift:12 — representative boundary

    @Environment(NavigationContext.self) private var navigationContext

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: SwiftDataAnimalsApp; View: AnimalCategoryListView, AnimalDetailContentView, AnimalDetailView, AnimalListView, ContentView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: removeAnimals, reloadSampleData, delete.
• Files: SwiftDataAnimals/SwiftDataAnimalsApp.swift, SwiftDataAnimals/Views/AnimalListView.swift, SwiftDataAnimals/Views/AnimalCategoryListView.swift, SwiftDataAnimals/Views/AnimalDetailView.swift, SwiftDataAnimals/Views/ContentView.swift, SwiftDataAnimals/Views/ThreeColumnContentView.swift.

Architecture takeaways

• SwiftDataAnimalsApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftData, SwiftUI through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation