Physical Design of Network Model Databases Using the Property of Separability

A physical design methodology for network model databases is dcvclopcd using the theory of separability. In particular, a large subset of practically important access structures provided by network model database systems is shown to have tic property of separability under the usage specification schcmc proposed. The theory of separability was introduced in an carlicr work, in the context of relational systems, as a formal basis for partitioning the problem of designing the optimal physical database. The theory proves that, given a certain set of access structures and a usage spccitication scheme, the problem of optimal assignment of access structures to the cntirc database can be reduced to the subproblem of optimizing individual record types indcpcndcntly of one another. The approach prcscntcd significantly rcduccs the complexity of the design problem which has the potential of being combinatorially explosive.