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:

1. Define table models with @Table macro
2. Use @FetchAll/@FetchOne property wrappers in views or @Observable models
3. Access database via @Dependency(\.defaultDatabase)
4. Perform writes in database.write { } transactions
5. Set up migrations before first use

Common Mistakes

1. 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.

2. Missing migrations on schema changes — Modifying @Table without creating a migration causes crashes at runtime. Always create migrations for schema changes before deploying.

3. Improper transaction handling — Long-running transactions outside of database.write { } block can cause deadlocks or data loss. Keep write blocks short and focused.

4. Ignoring CloudKit sync delegates — Setting up CloudKit sync without implementing SyncDelegate means you miss error handling and conflict resolution. Implement all delegate methods for production.

5. Over-fetching in SwiftUI views — Using @FetchAll without filtering/limiting can load thousands of records, freezing the UI. Use predicates, limits, and sorting to keep in-memory footprint small.