Dynamic Metasystems for Information Systems Development

Dynamics in the use of metasystems in the development ofinformation systemsis discussed. An axiomatic level of specification is used to allow dynamic specification of"median" level metasystems which are, in turn, used in information systems specification, analysis and design. Existing metasystems are reviewed and principles for metasystem evaluation are considered The implementation and use of dynamic metasystems in the Plexsys system is overviewed The Plexsys system implements generalized integrity analysis at alllevels of logic and mechanisms to insure the mutual integrity of these levels over time. Introduction tor of the integrity of models, The integrity of a model concerns its semantic completeness. An alternate metaparadigm is proposed. The paradigm draws on the A science is a well made language. -Condillac relationship of the me tasystems concept to semantics and knowledge representation in linquisucs and artiScial intelligence. The meta approach and system presented Computer-aided environments are evolving to facilitate allows for the generalization of a set of integrity rules for the specification and development of large-scale inforlanguage specifications and target system descriptions. mation systems. 'Ibols to support enterprise analysis, The implementation, which provides for dynamism of logical data and process modeling, database design, the overall three-tier model, is discussed in the final process organization, automatic code generation, and section. other design activities exhibit a variety of models, semantics, andterminology. A degree of dynamicsmustbe it*roducedifthedesignsupporttoolsaretobeeffective. These dynamics are fundamentally important as both The Metasystem Concept language definitions and target models change over time. That is, as more is learned about the organization In describing information systems, a large set of often and about the development process itself, the developdisjoint terminology is used among development settings ment environment must support the modification of In many cases, several terms are used to name a given " , . 44 relalanguage and target model definitions such that the term or concept For example, "record, group, models are internally and mumally complete and tion," and"data structure" have all been used to name a consistent conceptually analogous term Conceptual underpinnings, as well as the structure and One major drawback of many computer-aided methofunction of metasystems, are discussed in this paper. A dologies is thatthe predefined terms used inthe methometasystem framework of three basic definitionallevels dology may not be the same as the terms used by target is developed. Requirements foran effective metasystem system developers in any given setting. This drawback are outlined, including succinctness, dynamism, scope, leads to one of two outcomes; namely, the computerand granularity. Three metasystems used in information aided methodology will not be adopted, or it is adopted systems specifications-SEM, SDLA, and SDS-are withtheaccompanyingcostofreorientingallindividuals analyzed. The emphasis of the analysis is anassessment involved in systems development In the second outof the degree to which the metasystem can be a guarancome, extensive training of developers with respect to