John Carlis is on the faculty in the Department of Computer Science at the University of Minnesota. For the past twenty years he has taught, consulted, and conducted research on database systems, particularly in data modeling and database language extensions. Visit his homepage at www.cs.umn.edu/~carlis.
Joseph Maguire is an independent consultant and the creator of the forthcoming Web site www.logicaldatastructures.com. For the past 18 years he has been an employee or consultant for many companies, including Bachman Information Systems, Digital, Lotus, Microsoft, and US WEST.