This paper presents an analytical model to allocate files and workload simultaneously among heterogeneous servers that operate distributed databases on a two-level local multi-access computer network. The allocation problem is presented in the form of a non-linear integer programming model. The model incorporates both local processing and data communication overhead. The problem is NP-complete and thus a heuristic is developed. To illustrate its suitability, the heuristic is compared with an exhaustive enumeration method for small problems and with a genetic algorithm for large problems. Computational results imply that the heuristic provide effective database designs. (C) 1997 Elsevier Science Ltd.