Understanding relationships in SwiftData

Creating relationships between @Model classes in Swift, particularly when dealing with complex data models and SwiftUI, involves various techniques. These techniques mirror the types of relationships commonly found in databases and data modeling. Let’s take a look at the different ways to create relationships in @Model classes.

One-to-one relationships

Use a property to store the related model’s identifier or directly store an instance of the related model. A one-to-one relationship maps one object to a single instance of a related one, and you are not supposed to have multiple instances of the second object associated with the first one.

Let’s look at an example of a one-to-one relationship:

class UserProfile: ObservableObject {
      @Published var userId: UUID
      // Other properties
}
class User: ObservableObject {
     ...