When modeling information systems, one often encounters subtyping aspects of the business domain that can prove challenging to implement in either relational databases or object-oriented code. In practice, some of these aspects are often handled incorrectly. This chapter examines a number of subtyping issues that require special attention (e.g. derivation options, subtype rigidity, subtype migration), and discusses how to model them conceptually. Because of its richer semantics, the main graphic notation used is that of second generation Object-Role Modeling (ORM 2). However, the main ideas could be adapted for UML and ER, so these are also included in the discussion. A basic implementation of the proposed approach has been prototyped in Neumont ORM Architect (NORMA), an open-source tool supporting ORM 2.
Assessment of the regionalised demand response potential in Germany using an open source tool and dataset
