SwiftData schemas, queries, and migrations

Inputs

Inspect model/container registration, store configuration, context ownership, schema versions, deployment minimums, and whether synchronization is enabled.

Rules

• SD-001 — Own the graph. Define inverses and deletion behavior from domain lifecycle; neither cascade nor nullify is universally correct.
• SD-002 — Test translated queries. A predicate compiling in Swift does not prove store execution. Test real predicates, ordering, nil relationships, and limits on the supported store.
• SD-003 — Isolate mutable models. Keep context-bound objects on their intended actor; transfer identifiers or snapshots rather than live models.
• SD-004 — Treat schemas as history. Preserve shipped versions and test disk-backed upgrades. Never delete a failing store or switch silently to memory.
• SD-005 — Separate sync from save. Validate CloudKit constraints and account behavior; local uniqueness or a completed save is not distributed exactly-once delivery.

Workflow

1. Map each model and relationship to the configured schema and store.
2. Define draft/commit and query contracts before adding modifiers.
3. Choose a supported migration with realistic historical fixtures.
4. Exercise failures, relationships, reopens, and synchronization boundaries.

Verify

Test explicit saves through fresh contexts, failed commits, deletion graphs, query edge cases, and upgrades from every supported shipped schema. Label in-memory tests separately.

Output

Return schema/ownership decisions, query fixtures, upgrade evidence, and unverified store or account behavior.

References

• Models, contexts, and query correctness.
• Schema evolution and synchronization.