AN OBJECT-ORIENTED RULE-BASED APPROACH TO DATA MODEL AND SCHEMA TRANSLATION

To achieve data sharing among heterogeneous database management systems, one essential step is the conversion of the schemata defined in the diverse data models used by these systems. A semantic preserving translation of different modeling constructs and constraints is necessary to ensure that the semantics of applications remain intact after the translation. In this paper, we present an object-oriented extensible core model (ORECOM) which is used as a neutral, intermediate model through which diverse modeling constructs and constraints are translated. The model provides very general and primitive structural constructs in the forms of objects and binary object associations for representing the structural properties of various high-level data models. It also provides behavioral constructs in the forms of operation specifications and semantic rules with triggers for capturing the semantic constraints of these high-level models. Different from the intermediate models used in the existing heterogeneous database management systems, ORECOM is developed for supporting the translation among object-oriented and semantically rich data models. It is extensible in the sense that new modeling constructs and constraints can be added by extending the primitives of ORECOM. This paper also describes the design and implementation of a data model and schema translation system which is being used to test the conversions between the constructs and constraints of data models such as IDEF-1X, NIAM, EXPRESS, and OSAM*. Applications of this system include schema sharing, database conversion, and semantics modification and extension of schema. The techniques and methodology developed in this system are also useful for schema integration and schema design.