Time period set
A temporal element is a finite union of n-dimensional time intervals. Special cases of temporal elements include valid-time elements, transaction-time elements, and bitemporal elements, which are finite unions of valid-time intervals, transaction-time intervals, and bitemporal intervals, respectively.
Assuming an n-dimensional time domain, an interval is the product of n convex subsets drawn from each of the constituent dimensions.
Given a finite, one-dimensional time domain, a temporal element may be defined equivalently as a subset of the time domain. If the time domain is unbounded and thus infinite, some subsets of the time domain are not temporal elements. These subsets cannot be enumerated in finite space. For non-discrete time domains, the same observation applies.
Temporal elements are often used as timestamps. Unlike time periods, they are closed under the set theoretic operations of union, intersection, and complement, which is a...
- 1.Gadia SK. Temporal element as a primitive for time in temporal databases and its application in query optimization. In: Proceedings of the 13th ACM Annual Conference on Computer Science; 1986. p. 413.Google Scholar
- 3.Jensen CS, Dyreson CE, editors. A consensus glossary of temporal database concepts – February 1998 version. In: Etzion O, Jajodia S, Sripada S, editors, Temporal databases: research and practice. Berlin: Springer; 1998. p. 367–405.Google Scholar