Towards a spatio-temporal OQL for the four dimensional spatial database system Hawks

Discusses a spatio-temporal object query language (OQL), which treats spatial data and temporal data in the same way. We address spatial, temporal and spatio-temporal predicates and operators, and then show the queries in the spatio-temporal OQL and the ones in the internal expression of the spatio-temporal database system Hawks. This language is going to be implemented in INADA/ODMG, which is a database programming language based on C++ and which provides the C++ bindings of the ODMG-93 Object Database Standard. The expressions, in which spatio-temporal objects are defined as the figures of the 4D topological space resulting from the direct product of the 3D space and time, are used to retrieve those spatio-temporal objects which satisfy a condition.