The Partial Normalized Storage Model of Nested Relations

This paper introduces the partial normalized storage model of nested relations which uses the workload information of the database system under consideration to obtain a “better” storage model (i.e., one with a lower query cost) for a given nested relation. Based on the normalized storage model, the nested relation scheme is graphically represented as a tree called the scheme tree. By using the workload information, and by performing a series of merges on the nodes of the scheme tree. a near-optimum scheme tree is produced to represent the partial normalized storage model. We prove that our approach which uses the greedy method, locates the optimum scheme tree in most of the cases. In few cases, when the approach locates a “near” optimum scheme tree, the relative difference between the costs of the produced scheme tree and the optimum scheme tree is shown to be very small.