The Entity-Relationship Model
Read this chapter and pay attention to the main concepts, kinds of entities, types of attributes, and types of keys. Take notes on the three relationship types and complete the exercise at the end of the chapter.
Attributes
Each entity is described by a set of attributes (e.g., Employee = (Name, Address, Birthdate (Age), Salary).
Each attribute has a name, and is associated with an entity and a domain of legal values. However, the information about attribute domain is not presented on the ERD.
In the entity relationship diagram, shown in Figure 8.2, each attribute is represented by an oval with a name inside.
Figure 8.2. How attributes are represented in an ERD.