A data model for processes based on relative time

Advanced database applications such as automated manufacturing, scheduling, and computer-aided software engineering, demand an explicit representation of processes, including their decomposition into subprocesses, where subprocesses may be repeated or shared. Temporal information on these processes is inherently relative to particulartemporal frames of reference, that may be different from that of acomplex process containing them. We suggest the Rtime object-oriented data model in which processes are first-class citizens and complex processes are built, using standard type constructors, from their component processes. The relative timing of component processes is a key feature of the suggested model. It allows for a modular construction of complex process objects that may be repeated and shared. Standard object-oriented query languages can be used for temporal queries on processes, by providing an operator for translating timing information between different temporal frames of reference.