majiayu000 iOS Data & Persistence Router
You MUST use this skill for ANY data persistence, database, axiom-storage, CloudKit, or serialization work.
When to Use
Use this router when working with:
- Databases (SwiftData, Core Data, GRDB, SQLiteData)
- Schema migrations
- CloudKit sync
- File storage (iCloud Drive, local storage)
- Data serialization (Codable, JSON)
- Storage strategy decisions
Routing Logic
SwiftData
Working with SwiftData → /skill axiom-swiftdata
Schema migration → /skill axiom-swiftdata-migration
Migration issues → /skill axiom-swiftdata-migration-diag
Migrating from Realm → /skill axiom-realm-migration-ref
SwiftData vs SQLiteData → /skill axiom-sqlitedata-migration
Other Databases
GRDB queries → /skill axiom-grdb
SQLiteData → /skill axiom-sqlitedata
Advanced SQLiteData → /skill axiom-sqlitedata-ref
Core Data patterns → /skill axiom-core-data
Core Data issues → /skill axiom-core-data-diag
Migrations
Database migration safety → /skill axiom-database-migration (critical - prevents data loss)
Serialization
Codable issues → /skill axiom-codable
Cloud Storage
Cloud sync patterns → /skill axiom-cloud-sync
CloudKit → /skill axiom-cloudkit-ref
iCloud Drive → /skill axiom-icloud-drive-ref
Cloud sync errors → /skill axiom-cloud-sync-diag
File Storage
Storage strategy → /skill axiom-storage
Storage issues → /skill axiom-storage-diag
Storage management → /skill axiom-storage-management-ref
File protection → /skill axiom-file-protection-ref
Decision Tree
- SwiftData? → swiftdata, swiftdata-migration
- Core Data? → core-data, core-data-diag
- GRDB? → grdb
- SQLiteData? → sqlitedata, sqlitedata-ref
- ANY schema migration? → database-migration (ALWAYS — prevents data loss)
- Realm migration? → realm-migration-ref
- SwiftData vs SQLiteData? → sqlitedata-migration
- Cloud sync architecture? → cloud-sync
- CloudKit? → cloudkit-ref
- iCloud Drive? → icloud-drive-ref
- Cloud sync errors? → cloud-sync-diag
- Codable/JSON serialization? → codable
- File storage strategy? → storage, storage-diag, storage-management-ref
- File protection? → file-protection-ref
Anti-Rationalization
| Thought | Reality |
|---|---|
| "Just adding a column, no migration needed" | Schema changes without migration crash users. database-migration prevents data loss. |
| "I'll handle the migration manually" | Manual migrations miss edge cases. database-migration covers rollback and testing. |
| "Simple query, I don't need the skill" | Query patterns prevent N+1 and thread-safety issues. The skill has copy-paste solutions. |
| "CloudKit sync is straightforward" | CloudKit has 15+ failure modes. cloud-sync-diag diagnoses them systematically. |
| "I know Codable well enough" | Codable has silent data loss traps (try? swallows errors). codable skill prevents production bugs. |
Critical Pattern: Migrations
ALWAYS invoke /skill axiom-database-migration when adding/modifying database columns.
This prevents:
- "FOREIGN KEY constraint failed" errors
- "no such column" crashes
- Data loss from unsafe migrations
Example Invocations
User: "I need to add a column to my SwiftData model"
→ Invoke: /skill axiom-database-migration (critical - prevents data loss)
User: "How do I query SwiftData with complex filters?"
→ Invoke: /skill axiom-swiftdata
User: "CloudKit sync isn't working"
→ Invoke: /skill axiom-cloud-sync-diag
User: "Should I use SwiftData or SQLiteData?"
→ Invoke: /skill axiom-sqlitedata-migration