Goal

The central goal of this document is to provide the temporal database community with a comprehensive consensus benchmark for temporal query languages that is independent of any existing language proposal.

This is not a performance benchmark, but is rather a semantic benchmark intended to be an aid in evaluating the user-friendliness of proposals for temporal query languages. Thus, temporal query languages should ideally be able to express the benchmark queries both conveniently and naturally.

To obtain a consensus benchmark, researchers in temporal databases have been invited to participate in this initiative, and each researcher that has contributed significantly will be a coauthor. The electronic mail distribution tsql@cs.arizona.edu is used as the medium for discussing the benchmark and related issues.

As a consequence of the central goal above, no existing temporal data models are used or mentioned. The relation schemas of the benchmark are expressed as sets of attributes, including one attribute illustrating user-defined time. However, the underlying temporal aspects are implicit (of course, specific temporal data models might add explicit temporal attributes). The contents of the relations are described in natural language. The benchmark queries are also given only in natural language.

The benchmark is not intended to constitute a metric for query language completeness, and as such it is not a substitute for a rigorous theoretical study of expressive powers of various temporal query languages. Comprehensiveness of the benchmark is desirable only to ensure that all aspects of query language design are covered.

It it emphasized that using the benchmark as an advanced, quantitative scoring system for comparing languages makes little sense. Thus, one language is not necessarily superior to another just because one is capable of expressing more benchmark queries than the other. Rather, the focus is on user-friendliness.