swiftdata-patterns

Configuring a SwiftData ModelContainer for CloudKit sync requires specifying a CloudKit-backed configuration during container initialization. This skill provides instructions for on-disk stores, in-memory previews, and CloudKit-backed configurations.

Defining SwiftData relationships and delete rules requires declaring inverse relationships and setting sensible delete rules to keep the object graph consistent. This skill provides guidance on Relationship delete rules, inverse declarations, and object graph consistency.

Migrating a SwiftData schema using VersionedSchema involves defining VersionedSchema types and a SchemaMigrationPlan to map changes between versions. This skill covers VersionedSchema and SchemaMigrationPlan patterns, including lightweight versus custom migrations.

Writing type-safe predicates for SwiftData FetchDescriptor queries involves constructing predicate expressions and composing SortDescriptor objects. This skill provides examples for @Query, FetchDescriptor usage, SortDescriptor composition, and type-safe predicate construction.

SwiftData supports background persistence using ModelActor to execute database operations off the main thread. This skill includes patterns for background persistence via ModelActor alongside container configuration and migration planning.

You need custom SwiftData migrations instead of lightweight migrations when schema changes require complex data transformations or custom logic. This skill details VersionedSchema and SchemaMigrationPlan patterns, distinguishing between lightweight and custom migration approaches.