Enhancing the semantics of federated schemata by translating SQL-queries into object methods

Within the context of federated databases, considerable attention has been paid to the translation of relational export schemata of participating databases to a semantically richer common data model, such as the object-oriented model. Such a translation results in the definition of an object-oriented component schema for the local database. Each class definition in the component schema is a mapping of a set of attributes of one or more tables of the underlying relational schema. Component schemata are subsequently integrated into a federated schema. We argue that it is meaningful to extend the scope of the translation/integration process to include methods and constraints derived from applications on the underlying schemata. The component and federated schemata can thus be equipped with methods representing common queries on the underlying schemata and application-enforced constraints, enhancing the semantics of the schema, yielding a higher-level interface to federated applications, a..