Querying object evolution in temporal databases is interesting, but neither SOL-like algebraic languages nor general purpose languages take evolution into account. This paper presents a language, called the Event Matching Language, that is specifically designed for querying object evolution. The language is a pattern matching language based on the concept of cursor borrowed from SNOBOL4.

This paper deals with dimensional data. Examples of dimensions are space and time. Thus, temporal, spatial, spatiotemporal values are examples of dimensional data. We define the notion of dimensional object, extending an object-oriented ODMG-like type system to include dimensional types. We then address the problem of querying dimensional objects. Linguistic constructs are introduced that allow objects with different dimensions to be mixed in the same phrases. This allows the user to formulate both associative and navigational accesses seamlessly without having to worry about the dimensions of the various data elements involved.

We propose a pattern matching language for spatio-temporal databases. The matching process in time dimension is based upon the evolutionary nature of time, but in spatial dimension it is based on placement, shape and sizes of regions. The concept of pattern matching introduced in this paper is independent of the choice of the underlying model for spatio-temporal databases. In particular, the pattern matching language seamlessly extends our SQL-like query language ParaSQL for spatio-temporal databases. The pattern matching language would also have application in active databases, because patterns can be used as triggers.