This paper provides an overview of a methodology developed to support systems analysts in the process of database design. The design approach is built upon an analytic model composed of (1) parametric descriptions for components of a generalized database organization, (2) costing equations which can evaluate a proposed modular database design, (3) an analyst interface which accepts an arbitrary database organization for evaluation, and (4) search procedures which automatically generate and compare thousands of alternative designs. Performance is measured as the sum of storage, retrieval, and maintenance costs and is estimated from parameters of the proposed design, the problem description and the storage environment. A virtual, record-frame view of secondary storage has been developed in which data records are added, deleted and modified with minimal effect on existing data structures. Application of the modeling approach to a realistic design problem is described, and modeling accuracy to within four percent is claimed.