Swift 4 Protocol-Oriented Programming - Third Edition

Data model layer

There are two types defined in the data model layer. These types are used to transfer the data between the data helper layer and the bridge layer. Since these types should be used exclusively to transfer the data, using value types and, in particular, tuples, is preferred. Keep in mind that we want to avoid tightly coupling the business logic with the data access layer; therefore, these types should not be used outside the data access layer. If we avoid tightly coupling the business logic with the data access layer, we will have the ability to change either one independently of the other. The following code shows the types in the data model layer:

typealias TeamData = ( teamId: Int64?, city: String?, nickName: String?, abbreviation: ...