sqlite-data

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Translated

Use when working with SQLiteData library (@Table, @FetchAll, @FetchOne macros) for SQLite persistence, queries, writes, migrations, or CloudKit private database sync.

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Sourcejohnrogers/claude-swift-engineering

Added on2026-02-08

NPX Install

npx skill4agent add johnrogers/claude-swift-engineering sqlite-data

SKILL.md Content

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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.

Reference Loading Guide

ALWAYS load reference files if there is even a small chance the content may be required. It's better to have the context than to miss a pattern or make a mistake.

Reference	Load When
Table Models	Defining tables with `@Table` , setting up primary keys, columns, or enums
Queries - Basics	Using `@FetchAll` , `@FetchOne` , `@Selection` , filtering, ordering, or joins
Queries - Advanced	Using `@Fetch` with `FetchKeyRequest` , dynamic queries, recursive CTEs, or direct reads
Writes	Inserting, updating, upserting, deleting records, or managing transactions
Views - SwiftUI	Using `@FetchAll` / `@FetchOne` in SwiftUI views, `@Observable` models, or animations
Views - Integration	UIKit integration, dynamic query loading, TCA integration, or `observe {}`
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 - Queries	Implementing triggers, custom database functions, or full-text search (FTS5)
Advanced - Optimization	Performance tuning, indexes, custom aggregates, JSON aggregation, or self-joins
Schema Composition	Using `@Selection` column groups, single-table inheritance, or database views

Core Workflow

When working with SQLiteData:

Define table models with
```
@Table
```
macro
Use
```
@FetchAll
```
/
```
@FetchOne
```
property wrappers in views or
```
@Observable
```
models
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
```
@Table
```
without 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
```
SyncDelegate
```
means you miss error handling and conflict resolution. Implement all delegate methods for production.
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.