Time and Relational Theory

C. J. Date has a unique stature in the database industry. Author or coauthor of well over 30 books on database management (including the bestselling An Introduction to Database Systems, currently in its 8th edition), he enjoys a reputation that's second to none for his ability to explain complex technical issues in a clear and understandable fashion. He was inducted into the Computing Industry Hall of Fame in 2004. Hugh Darwen was employed in IBM's software development divisions from 1967 to 2004. In the early part of his career, he was involved in DBMS development; from 1978 to 1982, he was one of the chief architects of an IBM product called Business System 12, a product that faithfully embraced the principles of the relational model. He was an active participant in the development of the international standard for SQL (and related standards) from 1988 to 2004. Based in the UK, he currently teaches relational database theory at Warwick University and is a tutor and course development consultant for the Open University. He has written two books on database management as well as coauthoring several with C.J. Date. He has received honorary degrees from the University of Wolverhampton and the Open University. Nikos A. Lorentzos is a Professor at the Agricultural University of Athens. He is mainly known for his research in temporal (and also in spatio-temporal) databases. He has participated in relevant European Union funded projects (prime researcher for the development of a Temporal DBMS). The temporal model he has proposed has been extensively evaluated by independent researchers with positive comments, it is decribed in books addressed to university students, it has been the basis of PhDs undertaken in Europe and it has attracted the interest of DBMS developers. He is co-editor of the book Spatiotemporal Databases: The Chorochronos Approach (spatio-temporal databases). He is active in Temporal, Spatial and Spatio-temporal Databases as well as in the development of DSSs and Expert Systems in the forestry and the agricultural domain.