A business component definition represents a single business entity such as the customer, the products that a company sells, and the orders that customers make. When solution architects design business models they often use entity relationship diagrams (ERDs) to describe entities and their relationships to each other. The following diagram is an example for an ERD:

The diagram defines the entities Customer, Contact Person, Order, and Product. The crow's feet endpoints of the lines between the entity shapes represent a to many relationship. A customer can be associated with multiple contact persons while the same person can be associated with multiple customers. Relationships of this type are called many-to-many (M:M) and the typical graphical representation is a line with a crow's foot at each end. The preceding diagram also defines that a customer can place one or more orders each of which can consist of multiple products.

When the previous simplistic business...