Introduction

A technical language is an important infra-structural component of any scientific community. To be effective, such a language should be well-defined, intuitive, and agreed-upon.

This document contains proposals for definitions and names of a range of concepts specific to temporal databases that are well-defined, well understood, and widely used. The proposal meets a need for creating a higher degree of consensus on the definition and naming of central concepts from within the field. The use of inconsistent terminology adversely affects the accessibility of the literature—to members of the community as well as others—and has an adverse effect on progress.

Being a proposal, simply stating definitions and names would be counter-productive and against the intentions. Consequently, the proposals in the document generally include alternatives and discussions of why specific decisions were made. When several alternative names for concepts were considered, the document not only states the decisions, but it also presents the alternatives and discusses why the decisions were made.

The history of this document may be described as follows. An initial glossary of temporal database concepts arose from e-mail discussions when appropriate terminology was considered for the book Temporal Databases: Theory, Design, and Implementation, edited by A. Tansel, J. Clifford, S. Gadia, S. Jajodia, A. Segev, and R. Snodgrass, Benjamin/Cummings Publishers. That glossary also appeared in the September 1992 issue of the ACM SIGMOD Record. The efforts continued, independently of the book, and the community was invited to submit proposals to the mailing list tsql@cs.arizona.edu. As results, status documents appeared in December 1992 and in March 1993. All these previous documents are subsumed by the present document.

With the goal of obtaining a consensus glossary, the proposed concepts and names will be discussed during ``International Workshop on an Infrastructure for Temporal Databases,'' in Arlington, TX, June 1993. The objective of this workshop is to define and establish a common infrastructure of temporal databases and to develop a consensus base document that will provide a foundation for implementation and standardization as well as for further research.

The document is organized as follows. The following section constitutes the main part of the paper. It contains proposals for 68 concepts. A small section of 15 proposals follows. These proposals were submitted relatively late, and the community has not yet had the opportunity to fully discuss them. Two appendices follow which outline relevance and evaluation criteria for glossary entries. These criteria are referenced throughout the document. Finally, an index is included on the last page.