Hands-On Software Engineering with Python

Implementing the basic business objects in hms_sys

At this point in the development process, we simply don't know whether the exact same functionality for all of the business object classes will be in play in the two applications and the service that are going to be built. The data ownership rules—determination of what users can create, update, or delete what data inside an object—haven't been detailed enough to make those decisions yet. We do, however, have enough information, based solely on the purposes of those objects, to start defining what data they represent, and what constraints should exist around those data points.

We may have enough information here and now to know that certain functionalities need to exist for some of these object ...