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name: ios-data description: Master iOS data persistence - SwiftData, Core Data, Keychain, CloudKit sasmp_version: "1.3.0" version: "2.0.0" bonded_agent: 04-data-persistence bond_type: PRIMARY_BOND last_updated: "2024-12"

iOS Data Persistence Skill

Store, sync, and secure data in iOS applications

Learning Objectives

By completing this skill, you will:

• Implement data persistence with SwiftData (iOS 17+)
• Master Core Data for complex data models
• Secure sensitive data with Keychain
• Sync data across devices with CloudKit

Prerequisites

Storage Decision Matrix

Curriculum

Module 1: UserDefaults & AppStorage (2 hours)

Topics:

• UserDefaults basics
• @AppStorage in SwiftUI
• App Groups for sharing

Module 2: SwiftData (iOS 17+) (6 hours)

Topics:

• @Model macro
• ModelContext and @Query
• Relationships and migrations

Module 3: Core Data (6 hours)

Topics:

• NSManagedObject
• NSFetchRequest
• Background contexts
• Migrations

Module 4: Keychain (4 hours)

Topics:

• Keychain Services API
• Biometric access control
• Secure wrapper implementation

Module 5: CloudKit (5 hours)

Topics:

• CKContainer and databases
• CKRecord operations
• Sync strategies

Assessment Criteria

Skill Validation

1. Settings Manager: UserDefaults with AppStorage
2. Task App: SwiftData with relationships
3. Secure Vault: Keychain with biometrics
4. Syncing Notes: CloudKit integration