Tripod: a comprehensive system for the management of spatial and aspatial historical objects

Spatio-temporal databases have been the focus of considerable research attention in recent years. To date, much of this work has focused on the relational data model, with object data models receiving far less consideration. Where descriptions of such object models do exist, there is currently a lack of systems that build upon these models to produce database architectures that address the broad spectrum of issues related to the delivery for a fully fuctional spatio-temporal DBMS. This paper presents an overview of such a system by describing a spatio-historical object DBMS that utilises a specialised mechanism, called a history, for maintaining knowledge about entities that change over time. Key features of the resulting proposal include: (i) consistent representations of primitive spatial and temporal types; (ii) a component-based design in which spatial, temporal and historical extensions are formalised incrementally, for subsequent use together or separately; (iii) compatibility with mainstream query processing frameworks for object databases; and (iv) the integration of the spatio-temporal proposal with the ODMG standard.