Temporal Extension to ODMG

the past years a number of temporal extensions to the different database models have been proposed. Extensions to the relational model have been following the different SQL standards, while no attempts have been made to extend the OO-databases' standard, defined by ODMG. In this paper we present a temporal extension to the ODMG standard, as this has been specified in the TOOBIS project. A Temporal Object Data Model, a Temporal Object Definition Language and a Temporal Object Query Language have been specified and have been proposed as extensions to the ODM, ODL and OQL of ODMG. This extension has been implemented over a commercial OODBMS, reinforcing and validating the effort of standardisation and portability of this extension. 1. INTRODUCTION In the past years the management of temporal data has attracted numerous researchers resulting to a large number of extensions of the traditional database management systems to support temporal applications (Klopproge and Locke-Regarding extensions of existing standards, as well as trends for new standards, a first approach has been made in relational databases through TSQL2 Design Committee (1995), which is the result of a common work of researchers involved in temporal data in order to define a bitemporal extension of SQL92. (b)) presents a possible extension to the emerging SQL standard, keeping in mind TSQL2. However , insofar no extension to the ODMG standard (Cattel et al.; 1993) for object oriented databases has been proposed. In this paper we propose an approach for incorporating temporal data characteristics in object-oriented databases, in a compliant to ODMG way, taking into account the SQL/ Temporal proposal, as well as TSQL2. This proposal is made through the TOOBIS 1-Temporal Object-Oriented dataBases within Information Systems-project, which is an Esprit IV program. Most of the extensions listed above focus on some specific points of temporal databases. The TOOBIS extension to ODMG aims to supply temporal data management within a