Grdb

GRDB

Direct SQLite access using GRDB.swift - type-safe Swift wrapper with full SQLite power when you need it.

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 | |-----------|-----------| | [Getting Started](references/getting-started.md) | Setting up DatabaseQueue or DatabasePool | | [Queries](references/queries.md) | Writing raw SQL, Record types, type-safe queries | | [Value Observation](references/value-observation.md) | Reactive queries, SwiftUI integration | | [Migrations](references/migrations.md) | DatabaseMigrator, schema evolution | | [Performance](references/performance.md) | EXPLAIN QUERY PLAN, indexing, profiling |

When to Use GRDB vs SQLiteData

| Scenario | Use | |----------|-----| | Type-safe @Table models | SQLiteData | | CloudKit sync needed | SQLiteData | | Complex joins (4+ tables) | GRDB | | Window functions (ROW_NUMBER, RANK) | GRDB | | Performance-critical raw SQL | GRDB | | Reactive queries (ValueObservation) | GRDB |

Core Workflow

1. Choose DatabaseQueue (single connection) or DatabasePool (concurrent reads)
2. Define migrations with DatabaseMigrator
3. Create Record types (Codable, FetchableRecord, PersistableRecord)
4. Write queries with raw SQL or QueryInterface
5. Use ValueObservation for reactive updates

Requirements

• iOS 13+, macOS 10.15+
• Swift 5.7+
• GRDB.swift 6.0+

Common Mistakes

1. Performance assumptions without EXPLAIN PLAN — Assuming your query is fast or slow without checking EXPLAIN QUERY PLAN is guessing. Always profile queries with EXPLAIN before optimizing.

1. Missing indexes on WHERE clauses — Queries filtering on non-indexed columns scan the entire table. Index any column used in WHERE, JOIN, or ORDER BY clauses for large tables.

1. Improper migration ordering — Running migrations out of order or skipping intermediate versions breaks schema consistency. Always apply migrations sequentially; never jump versions.

1. Record conformance shortcuts — Not conforming Record types to PersistableRecord or FetchableRecord correctly leads to silent data loss or deserialization failures. Always implement all required protocols correctly.

1. ValueObservation without proper cleanup — Forgetting to cancel ValueObservation when views disappear causes memory leaks and stale data subscriptions. Store the cancellable and clean up in deinit.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: johnrogers
• Source: johnrogers/claude-swift-engineering
• License: MIT

Install and usage instructions live in the source repository linked above.