Spatio-temporal databases are a topic of growing research interest but there is still little work reported on spatio-temporal query languages in line with the Object Database Management Group (ODMG) standard. This paper presents the design of such a language, called STOQL, by adding spatial and temporal dimensions to OQL. This language is based upon a data model that extends the ODMG Object Model with basic spatial and temporal types as well as a parameterised type, Temporal, which lifts

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... types into spatio-temporal types to support the representation of the history of an object. We show that STOQL can support the formulation of various spatio-temporal queries in relation to historical states of spatial objects as well as spatial changes including spatial type substitution.