Chapter 2, Problem 2.24PAE

For each of the descriptions below, perform the following tasks:

i. Identify the degree and cardinalities of the relationship.

ii. Express the relationships in each description graphically with an E-R diagram.

a. A book is identified by its ISBN number, and it has a title, a price, and a date of publication. It is published by a publisher, which has its own ID number and a name. Each book has exactly one publisher, but one publisher typically publishes multiple books over time.

b. A book (see 2a) is written by one or multiple authors. Each author is identified by an author number and has a name and date of birth. Each author has either one or multiple books; in addition, occasionally data are needed regarding prospective authors who have not yet published any books.

c. In the context specified in 2a and 2b, better information is needed regarding the relationship between a book and its authors. Specifically, it is important to record the percentage of the royalties that belongs to a specific author, whether or not a specific author is a lead author of the book, and each author's position in the sequence of the book's authors.

d. A book (see 2a) can be part of a series, which is also identified as a book and has its own ISBN number. One book can belong to several sets, and a set consists of at least one but potentially many books.

e. A piano manufacturer wants to keep track of all the pianos it makes individually. Each piano has an identifying serial number and a manufacturing completion date. Each instrument represents exactly one piano model, all of which have an identification number and a name. In addition, the company wants to maintain information about the designer of the model. Over time, the company often manufactures thousands of pianos of a certain model, and the model design is specified before any single piano exists.

f. A piano manufacturer (see 2e) employs piano technicians who are responsible for inspecting the instruments before they are shipped to the customers. Each piano is inspected by at least two technicians (identified by their employee number). For each separate inspection, the company needs to record its date and a quality evaluation grade.

g. The piano technicians (see 2f) have a hierarchy of reporting relationships: Some of them have supervisory responsibilities in addition to their inspection role and have multiple other technicians report to them. The supervisors themselves report to the chief technician of the company.

h. A vendor builds multiple types of tablet computers. Each has a type identification number and a name. The key specifications for each type include amount of storage space and display type. The company uses multiple processor types, exactly one of which is used for a specific tablet computer type; obviously, the same processor can be used in multiple types of tablets.

Each processor has a manufacturer and a manufacturer's unique code that identifies it.

i. Each individual tablet computer manufactured by the vendor (see 2h) is identified by the type identification number and a serial number that is unique within the type identification. The vendor wants to maintain information about when each tablet is shipped to a customer.

j. Each of the tablet computer types (see 2h) has a specific operating system. Each technician the company employs is certified to assemble a specific tablet type—operating system combination. The validity of a certification starts on the day the employee passes a certification examination for the combination, and the certification is valid for a specific period of time that varies depending on tablet type—operating system combination.