title: Extended relational operators for statistical data manipulations in medical databases.
abstract: Conventional relational database management systems fail to address three features of statistical data management in a biomedical/clinical database, namely, that (1) statistical and medical data (SMD) require a great deal of space and need to be stored in a reduced form with minimal duplication; indeed, SMD have many derived/calculated and summary statistics that make the number of attributes in a relation (i.e., a set of records) grow rapidly and dynamically; (2) most SMD have hierarchical structures that are difficult to manage using the relational data model since SMD are stored in separate relations for duplication and space considerations; and (3) the management of SMD is made easier if it is possible to reorganize relations or group data, a capability lacking in conventional relational database management systems. In this paper, we (1) introduce five extended relational operators, (lattice) NEST, (lattice) UNNEST, MERGE, SPREAD, and GEN, to reorganize relations; (2) integrate the extended operators with conventional relational algebra and introduce the concept of the lattice relational model; and (3) give applications of the extended relational operators and the lattice relational model in solving the problems of statistical data manipulation in medical databases.
authors.affiliation: Department of Computer Engineering and Science, Case Western Reserve University, Cleveland, Ohio 44106.
authors.forename: H H
authors.initials: HH
authors.lastname: Yao
authors.forename: T S
authors.initials: TS
authors.lastname: Yamashita
mesh_terms: D003628:Database Management Systems; D006753:Hospital Records; D006801:Humans; D008432:Mathematical Computing; D008492:Medical Informatics Computing; D012984:Software