Swiftdata
Implement, review, or improve data persistence using SwiftData.
Install
npx skills add dpearson2699/swift-ios-skills --skill swiftdata -g -a claude-code -y- Repository
- dpearson2699/swift-ios-skills1.3k
- Category
- Mobile
- Updated
- 3mo ago
- License
- See repository
- Context cost
- Mediumabout 3,000 tokens
- Runs scripts
- No, instructions only
What it does
Implement, review, or improve data persistence using SwiftData. Use when defining @Model classes with @Attribute, @Relationship, @Transient, #Unique, or #Index; when querying with @Query, #Predicate, FetchDescriptor, or SortDescriptor; when configuring ModelContainer and ModelContext for SwiftUI or background work with @ModelActor; when planning schema migrations with VersionedSchema and SchemaMigrationPlan; when setting up CloudKit sync with ModelConfiguration; or when coexisting with or migrating from Core Data.
SwiftData
Persist, query, and manage structured data in iOS 26+ apps using SwiftData with Swift 6.3.
Contents
- Model Definition
- ModelContainer Setup
- CloudKit Sync
- CRUD Operations
@Query in SwiftUI- #Predicate
- FetchDescriptor
- Schema Versioning and Migration
- Core Data Coexistence Boundary
- Concurrency (
@ModelActor) - SwiftUI Integration
- Common Mistakes
- Review Checklist
- References
Model Definition
Apply @Model to a class (not struct). It synthesizes PersistentModel
conformance. Model instances remain context/actor-bound; pass their
PersistentIdentifier, not the instance, across actors.
@Model
class Trip {
var name: String
var destination: String
var startDate: Date
var endDate: Date
var isFavorite: Bool = false
@Attribute(.externalStorage) var imageData: Data?
@Relationship(deleteRule: .cascade, inverse: \LivingAccommodation.trip)
var accommodation: LivingAccommodation?
@Transient var isSelected: Bool = false // Always provide default
init(name: String, destination: String, startDate: Date, endDate: Date) {
self.name = name; self.destination = destination
self.startDate = startDate; self.endDate = endDate
}
}
@Attribute options: .externalStorage, .unique, .spotlight, .allowsCloudEncryption, .preserveValueOnDeletion, .ephemeral, .transformable(by:). Rename: @Attribute(originalName: "old_name").
@Relationship: deleteRule: .cascade/.nullify(default)/.deny/.noAction. Specify inverse: for reliable behavior. Unidirectional (iOS 18+): inverse: nil.
