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 | Setting up DatabaseQueue or DatabasePool | | Queries | Writing raw SQL, Record types, type-safe queries | | Value Observation | Reactive queries, SwiftUI integration | | Migrations | DatabaseMigrator, schema evolution | | Performance | 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
- Choose DatabaseQueue (single connection) or DatabasePool (concurrent reads)
- Define migrations with DatabaseMigrator
- Create Record types (Codable, FetchableRecord, PersistableRecord)
- Write queries with raw SQL or QueryInterface
- Use ValueObservation for reactive updates
Requirements
- iOS 13+, macOS 10.15+
- Swift 5.7+
- GRDB.swift 6.0+
Common Mistakes
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Performance assumptions without EXPLAIN PLAN — Assuming your query is fast or slow without checking
EXPLAIN QUERY PLANis guessing. Always profile queries with EXPLAIN before optimizing. -
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.
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Improper migration ordering — Running migrations out of order or skipping intermediate versions breaks schema consistency. Always apply migrations sequentially; never jump versions.
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Record conformance shortcuts — Not conforming Record types to
PersistableRecordorFetchableRecordcorrectly leads to silent data loss or deserialization failures. Always implement all required protocols correctly. -
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.