Sectioned Queries in SwiftData (iOS 27)

You've always been able to fetch SwiftData objects. But grouping them into sections for lists meant manual dictionaries, sorting, and transformation code.

iOS 27 changes that.

What's covered:

• Creating SwiftData models with relationships
• Using @Query(sectionBy:) — the new parameter
• Building sectioned SwiftUI lists automatically
• Working with relationships between categories and expenses
• Previewing SwiftData apps with sample data

Real example: A budgeting app where expenses are grouped by budget category — no manual grouping code required.