A technology company provides offerings to its customers. Offerings are of two separate types: products and services. Offerings are identified by an offering ID and an attribute of description. In addition, products are described by product name, standard price, and date of first release; services are described by name of the companys unit responsible for the service and conditions of service.

There are repair, maintenance, and other types of services. A repair service has a cost and is the repair of some product; a maintenance service has an hourly rate. Fortunately, some products never require repair. However, there are many potential repair services for a product.

A customer may purchase an offering, and the company needs to keep track of when the offering was purchased and the contact person for that offering with the customer. Unfortunately, not all offerings are purchased. Customers are identified by customer ID and have descriptive data of name, address, and phone number.

When a service is performed, that service is billed to some customer. Because some customers purchase offerings for their clients, a customer may be billed for services he or she did not purchase, as well as for ones that were purchased. When a customer is billed for a service (although some may never require a service of any type), the company needs to keep track of the date the service was performed, the date the bill is due, and the amount due.

1. Please identify the entities, their attributes, and their relationships as suggested in the problem above:

2. Are there any supertype/subtype relationships present? If so, what entities would be involved? Which would be the supertype, and which would be the subtype?

3. Now consider the completeness constraint. In the supertype/subtype relationship identified above a total specialization rule or a partial specialization rule? What does this mean for this/these relationship(s)?

4. Now consider the disjointness Constraints. Is this a disjoint rule or an overlapping rule? What does that mean for this/these relationship (s)?

5. Now let us consider the subtype discriminator. How would you describe the subtype discriminator for this supertype/subtype relationship? Is it a simple attribute, or a composite attribute?

6. Now let us consider the subtype discriminator. How would you describe the subtype discriminator for this supertype/subtype relationship? Is it a simple attribute, or a composite attribute?