CSci 455

A group exercise

Due: Tuesday, Feb. 19 (next Tuesday)

Step 1: Break into groups of three. I'll do that at the start.

Step 2: Consider the write-up at the bottom of this page. Make initial decisions about entities, attributes, and relations. Construct an entity-relationship diagram.

This is probably about as far as we can get during class. If transparency sheets are available, I will ask for volunteers to present the work so far.

Step 3: From the entity-relationship diagram, construct a relational schema. Clearly identify keys and foreign keys.

Turn it (in class, Tuesday) a clean copy of the entity-relationship diagram and relational schema.

A. At YoyoDyne corporation, employees are assigned to groups. Each group has a supervisor. Employees work on a variety of projects, devoting a percentage of their time to each project. Projects are supervised by one employee, and may have a number of employees working on them. Each project is tied to a contract which has a contract number, date signed, and a completion date. YoyoDyne works with a number of companies, but each contract is written with only one company.

B. An ongoing series of classes available from a distance learning center are available at any time for employees who may take a given class as often as they would like. No grade is given for classes, but successful completion of a class results in an employee's gaining a particular skill code.