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Version propagation in federated database systems

Integrated engineering environments, based on federated database technology, are, among others, a means to control the integrity of and dependencies between product data created in many different engineering applications. Most of these applications support the management of versions of a product and its parts, continuing the engineers' tradition of keeping different versions of drawings and documents. Consequently, federations in engineering environments have to provide version management on their global layer as well. The paper discusses the concepts for a flexible and customisable realisation of the federated database management system's version propagation service. This service is responsible for making a new local version "visible" at the global layer of the federation and vice versa. It tries to identify properties like a new version's history and predecessor automatically. We show how these properties can (and sometimes must) be completed or updated if they are incomplete, inapplicable, or even contradictory. We conclude that the customisation overhead is inevitable for any general solution bridging highly heterogeneous versioning models.