sqlite-data
Use when working with SQLiteData library (@Table, @FetchAll, @FetchOne macros) for SQLite persistence, queries, writes, migrations, or CloudKit private database sync.
When & Why to Use This Skill
This Claude skill is a specialized assistant for the SQLiteData library, designed to streamline Swift development with type-safe SQLite persistence. It helps developers leverage Swift macros for database modeling, manage complex CloudKit private database synchronizations, and implement efficient data fetching patterns. By providing guidance on migrations, transactions, and performance optimization, it ensures robust and scalable data management for modern iOS and macOS applications.
Use Cases
- Defining type-safe database models using @Table macros to automate boilerplate code and ensure schema integrity.
- Implementing seamless CloudKit private database synchronization with custom sync delegates and conflict resolution strategies.
- Optimizing SwiftUI or TCA-based applications by integrating @FetchAll and @FetchOne property wrappers for reactive data loading.
- Managing database schema evolution through structured migrations and the DatabaseMigrator to prevent runtime crashes.
- Improving application performance by identifying and resolving N+1 query patterns and optimizing transaction handling.
- Setting up comprehensive unit tests for database logic, including data seeding and assertion of SQLite operations.
| name | sqlite-data |
|---|---|
| description | Use when working with SQLiteData library (@Table, @FetchAll, @FetchOne macros) for SQLite persistence, queries, writes, migrations, or CloudKit private database sync. |
SQLite Data
SQLiteData provides type-safe SQLite access through Swift macros, simplifying database modeling and queries while handling CloudKit sync, migrations, and async patterns automatically.
Overview
Quick Reference
| Reference | Load When |
|---|---|
| Table Models | Defining database tables with @Table macro, setting up primary keys, columns, or enums |
| Queries | Using @FetchAll, @FetchOne, @Fetch property wrappers, or building queries with joins/filters |
| Writes | Inserting, updating, upserting, or deleting records; managing transactions |
| Views | Integrating @FetchAll/@FetchOne with SwiftUI views, @Observable models, UIKit, or TCA @ObservableState |
| Migrations | Creating database migrations with DatabaseMigrator or #sql() macro |
| CloudKit Sync | Setting up CloudKit private database sync, sharing, or sync delegates |
| Dependencies | Injecting database/sync engine via @Dependency, bootstrap patterns, or TCA integration |
| Testing | Setting up test databases, seeding data, or writing assertions for SQLite code |
| Advanced | Implementing triggers, full-text search (FTS5), or custom database functions |
| Schema Composition | Using @Selection column groups, single-table inheritance, or database views |
Core Workflow
When working with SQLiteData:
- Define table models with
@Tablemacro - Use
@FetchAll/@FetchOneproperty wrappers in views or@Observablemodels - Access database via
@Dependency(\.defaultDatabase) - Perform writes in
database.write { }transactions - Set up migrations before first use
Common Mistakes
N+1 query patterns — Loading records one-by-one in a loop (e.g., fetching user then fetching all their posts separately) kills performance. Use joins or batch fetches instead.
Missing migrations on schema changes — Modifying
@Tablewithout creating a migration causes crashes at runtime. Always create migrations for schema changes before deploying.Improper transaction handling — Long-running transactions outside of
database.write { }block can cause deadlocks or data loss. Keep write blocks short and focused.Ignoring CloudKit sync delegates — Setting up CloudKit sync without implementing
SyncDelegatemeans you miss error handling and conflict resolution. Implement all delegate methods for production.Over-fetching in SwiftUI views — Using
@FetchAllwithout filtering/limiting can load thousands of records, freezing the UI. Use predicates, limits, and sorting to keep in-memory footprint small.