Practice

ER Modeling

Create an Entity$-$Relationship Diagram for a car dealership. The dealership sells both new and used cars, and it operates a service facility. Base your design on the following business rules:

A salesperson may sell many cars, but each car is sold by only one salesperson.

A customer may buy many cars, but each car is bought by only one customer.

A salesperson writes a single invoice for each car he or she sells.

A customer gets an invoice for each car he or she buys.

A customer may come in just to have his or her car serviced; that is$,$ a customer need not buy a car to be classified as a customer.

When a customer takes one or more cars in for repair or service, one service ticket is written for each car.

A car brought in for service can be worked on by many mechanics, and each mechanic may work on many cars.

Mechanics are specialized in different areas of repair such as engine, bodywork, or electrical systems and is important to know the expertise level in each area.

Important:

Identifiers should be placed at the top of the attributes list and clearly distinguished. They can be underlined or bold to ensure easy recognition.

For all relationships, identify maximum and minimum cardinalities

Attributes should be associated with their respective entities. Foreign keys should not be included in your model as they are not identified at the modeling stage.

Document all assumptions made that are not explicitly stated in the specifications.

Submit a document that includes the names of the students, additional specifications $($including assumptions made$),$ and the Entity$-$Relationship Diagram.