macos-swiftdata-architecture

What problem does it solve?

Many macOS apps struggle with inefficient SwiftData schemas, slow or unsafe queries, hard-to-test persistence layers, and costly migrations; this Skill helps teams design robust, maintainable, and high-performance data layers for SwiftData-based applications. It clarifies when to use @Model vs value types, how to apply unique constraints and relationship delete rules, and how to avoid common thread-safety and memory pitfalls.

Core Features & Use Cases

• Schema design: advice on @Model structure, unique constraints, attribute options, and delete rules to prevent duplication and data corruption.
• Query patterns: recommendations for using @Query in views, FetchDescriptor in services, predicates, sorting, pagination, and identifiers-only fetches to minimize memory.
• Repository pattern & testing: guidance on DTO mapping, protocol-based repositories, in-memory test implementations, dependency injection, and actor isolation for thread safety.
• Performance & migrations: batch import/delete strategies, background context usage, context resets, measuring with Instruments, and migration planning for complex schema changes.
• Use Case: migrating a legacy Core Data app to SwiftData while preserving performance and adding unit-testable data access layers.

Quick Start

Analyze my macOS SwiftData models and provide a prioritized list of schema, query, repository, and migration changes to improve performance and testability.