Point vs. interval-based query languages for temporal databases (extended abstract)
David Toman · 1996
) David Toman Department of Computer Science, University of Toronto Toronto, Ontario, Canada M5S 1A4 [email protected] Abstract In this paper we establish a correspondence between two major views of temporal databases and the corresponding firstorder temporal query languages: the point-based view of temporal databases vs. the interval-based view of temporal databases. We show that all first-order queries can be conveniently asked using a point-based first-order query languages in a much more declarative and natural way and then mechanically translated into an interval-based query language, e.g., TSQL2. Such an approach combines the ease of formulating queries in first-order logic (temporal relational calculus) with the efficient query evaluation algorithms developed for the interval-based temporal databases. 1 Introduction In this paper we try to fill the gap between two main directions of research in the area of temporal databases and temporal query languages: The first direct...