Journal of Visual Languages and Computing (2000) 11, 663}685 doi:10.1006/jvlc.2000.0184 available online at http://www.idealibrary.com on An Extended Relational Data Model for Multimedia DBMSs G. POLESE,* A. PANNELLA AND G. TORTORA Dipartimento di Matematica e Informatica, University of Salerno, Italy,  giupol, antpan, jentro@unisa.it Received 3 December 1999; accepted 21 June 2000 We have extended the canonical relational data model to enable the management of multimedia objects. In an attempt to provide a smooth paradigm shift to multimedia information system development, we have enhanced the relational data model frame- work with techniques for modeling, storing and manipulating multimedia data. In particular, we have provided a graphical conceptual model for structuring a multimedia document and mapping rules for translating it into an extended relational data schema. Extensions have regarded the management of foreign keys, active components, mecha- nisms for the management of spatial and temporal relations, and finally functions for handling multimedia presentations. As a consequence, we have also provided exten- sions to the SQL language to handle these new mechanisms.  2000 Academic Press Keywords: multimedia document, RDBMS, SQL3, spatial relation, temporal relation, multimedia presentation, content-based retrieval. 1. Introduction TRADITIONALLY, DATA TYPES like images and sounds have been processed in an analogical fashion. Due to the increased power of modern computer systems, nowadays these data types are digitally processed, which has made it possible to develop com- puterized multimedia information systems. Most existing approaches for multimedia system development rely on object-oriented DBMS technology (ODBMS) [1, 2]. Example are the systems CORE [3], OOCM [4], and VODAK [5]. Although the maturity of ODBMS technology has progressed, its exploitation is still a challenge, because it entails a costly paradigm shift for companies willing to introduce the processing of multimedia information within their traditional information systems. In this paper, we present an extended relational data model for multimedia DBMSs that allows us to efficiently model, store, retrieve and present multimedia documents. We believe that a relational multimedia DBMS allows companies to perform a smoother migration towards multimedia information systems. * Corresponding author. 1045-926X/00/120663 # 23 $35.00/0  2000 Academic Press