ios-data

Data persistence strategy depends on your app's requirements. SwiftData offers modern Swift integration with less boilerplate; Core Data provides mature ecosystem support; SQLite and GRDB enable custom query control. This Skill routes you through decision trees for each format, migrations, and cloud-sync integration to match your offline-first or cloud-connected architecture.

iOS database migrations require invoking the database-migration path when adding or modifying columns. This Skill enforces critical migration patterns across SwiftData, Core Data, GRDB, and SQLite, covering schema changes, data transformation, and rollback strategies to prevent data loss.

CloudKit and iCloud Drive syncing involves routing serialization tasks and managing cloud storage strategies. This Skill covers end-to-end cloud-sync guidance, including Codable integration, conflict resolution, and when to use CloudKit versus file-based iCloud storage for your persistence layer.

Codable works alongside Core Data and GRDB for serialization but requires careful routing. This Skill guides serialization patterns, showing when Codable alone suffices versus when to combine it with database-specific encoding, and how to handle format conversions across storage types.

iOS file storage includes document directories, temporary caches, and app groups. This Skill routes you through file-storage strategy decisions, covering when to use flat files with Codable versus databases, storage permissions, and integration with CloudKit for synced persistence.

SwiftData migration from Core Data requires planning schema mapping and data transformation. This Skill enforces migration patterns, routing the transition path, handling Codable conversion, and ensuring cloud-sync continuity during the switch between persistence frameworks.