Understanding generalizations and specializations of entities
The concept of generalization and specialization (or inheritance as it is often referred to) can be a little tricky to wrap your head around if you don't already have experience with it. The basic concept is that generalization entities sit at the top of the hierarchy and specializations are customizations of the generalization entity. Figure 11.10 shows what this would look like in the domain model:
Figure 11.10 – Domain model with generalization and specialization entities
As shown in Figure 11.10, one example to help better explain this would be if you had a domain model with an entity called Vehicle. Vehicle contains attributes that would be common for any vehicle, such as Color, YearBuilt, and Weight. However, the application deals with very specific classes of vehicles: vehicles that travel on land and vehicles that travel through the air. In this case, you decide to create specialization...
