Skip to Main Content
Time and Relational Theory, 2nd Edition
book

Time and Relational Theory, 2nd Edition

by C.J. Date, Hugh Darwen, Nikos Lorentzos
August 2014
Advanced content levelAdvanced
560 pages
15h 32m
English
Morgan Kaufmann
Content preview from Time and Relational Theory, 2nd Edition
Appendix A

Cyclic Point Types

Point types are usually assumed to have a first (minimum) and last (maximum) value. This appendix concerns itself with point types such as days of the week for which that assumption isn’t necessarily valid. For example, in the case of days of the week, an interval such as “Friday to Tuesday” does make sense, at least intuitively. Allen’s operators are reexamined in this light and are found still to be applicable, though their definitions need to be refined somewhat. The same goes for the interval UNION, INTERSECT, and MINUS operators, also for the PACK and UNPACK operators.

Keywords: cyclic type; periodic type; wraparound interval; Allen’s operators

What goes around comes around.

—late 20th century catchphrase

All ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

The Circuit Designer's Companion, 4th Edition

The Circuit Designer's Companion, 4th Edition

Peter Wilson
3D User Interfaces: Theory and Practice

3D User Interfaces: Theory and Practice

Doug A. Bowman, Ernst Kruijff, Joseph J. LaViola Jr., Ivan Poupyrev

Publisher Resources

ISBN: 9780128006313