Enterprise Software with Half-Duplex Interoperations

In [3] the author and his colleague Dampney showed how a new solution to view update problems based on a category theory can be used to support enterprise information system interoperation. We now have considerable experience in applying that technique in industry. One of the major applications has been to developing interoperations between large databases. The view update approach to interoperations provides reasonable functionality while limiting the modifications needed to implement it. However, for mathematical reasons the view update approach to interoperations requires a significant amount of attribute harmonisation which means that companies must share data that they sometimes view as confidential. In testing this approach it has become apparent that, like full-duplex communications , it guarantees interoperations in both directions between the cooperating databases. However, in the systems tested interoperations were frequently necessary in one direction only for particular actions (inserts or deletes) on particular entities. This paper introduces a " half-duplex " approach to designing interoperations between extant systems in which data flows both ways between the systems, but on any action on any particular entity it will only flow one way. This significantly extends the domain of application of the technique by avoiding the former need to share information which some organisations insisted on keeping confidential.