Identifying a Forest Hierarchy in an OODB Specification Hierarchy Satisfying Disciplined Modeling

Our work is motivated by the desire to develop methods to comprehend large vocabularies and large schemas of Object-Oriented Databases. The ability of a user of a database participating in a federated system to retrieve information from the other database systems will be greatly enhanced by acquiring a better comprehension of these systems. We are trying to develop both a theoretical paradigm and a methodology to analyze existing large schemas. Our approach to achieve comprehension is based on combining two concepts: informational thinning (i.e. concentration on the specialization hierarchy of the schema) and partitioning. In this paper we present a new technique for modeling which is called disciplined modeling. Based on the rules of disciplined modeling we develop a theoretical paradigm to support the existence of a meaningful forest hierarchy within the specialization hierarchy. Such a hierarchy functions as a skeleton of the schema and supports comprehension and partitioning eeorts. 1 Motivation One of the problems in cooperative information systems is that the user of each system is familiar with his own applications, databases and terminologies, but he is much less familiar with those of the other systems. Therefore, the cooperation suuers from the lack of comprehension of the schemas and terminologies used in the other federated systems. Our work is motivated by the desire to comprehend large vocabularies and schemas of Object-Oriented Databases (OODB) and to develop methods to make them understandable for users. We are developing a theoretical framework and a methodology which will enable the design of tools to aid comprehension of existing OODB systems. Graphical presentation is a very important tool to support schema comprehension. Thus, we assume that schemas and vocabularies are represented with a graphical schema language and manipulated with a graphical editor. Our approach to achieve comprehension of graphical schemas is based on two concepts: informational thinning (i.e. concentration on the specialization hierarchy) and partitioning. In this paper we present a new technique for mod-eling called disciplined modeling. Based on the rules of disciplined modeling we develop a theoretical paradigm to support the existence of a meaningful forest within a specialization hierarchy. This forest represents a partitioning of the specialization hierarchy into trees and functions as a skeleton of the schema that supports comprehension eeorts. In 1] we will present a methodology based on our paradigm for nding a forest hierarchy for a given schema. This research is part of our current OOHVR …