In order to have a more complete class hierarchy, we must take into account that a university has not only employees, but students as well. To add this, refer to the Workstudy View, which shows the attributes in the Student relational base table. From this, the Entry Date can be factored up into a Student Class as shown below. This introduces multiple inheritance to this object schema where the Workstudy class inherits attributes from both Teacher and Student. You should note that not all programming languages can support multiple inheritance. Nevertheless, it is important to understand the concept.
Yes, there are still redundant attributes in the Student and Employee classes. They will be addressed in the next step.
Next: Adding the Person Class to the hierarchy. Also see the related content below.
Context for Adding the Student Class to the Hierarchy
Related Articles for Adding the Student Class to the Hierarchy
The Savvy Manager's Guide
Douglas K Barry is also the author of a book that explains Web Services, service-oriented architecture, and Cloud Computing in an easy-to-understand, non-technical manner.
Web Services, Service-Oriented Architectures, and Cloud Computing: The Savvy Manager's Guide (Second Edition)
by Douglas K Barry with David Dick
This is a guide for the savvy manager who wants to capitalize on the wave of change that is occurring with Web Services, service-oriented architecture, and—more recently—Cloud Computing. The changes wrought by these technologies will require both a basic grasp of the technologies and an effective way to deal with how these changes will affect the people who build and use the systems in our organizations. This book covers both issues. Managers at all levels of all organizations must be aware of both the changes that we are now seeing and ways to deal with issues created by those changes.