Due to the current technological and economical context, there is an increasing need for cooperating information systems based on federated databases. Though the technical issues of these architectures have been studied for long, the way to build them has not triggered as much effort. This paper describes a general architecture, a methodology and a CASE environment intended to address the problem of providing users and programmers with an abstract interface to independent heterogeneous and distributed databases. The architecture comprises a hierarchy of mediators and a repository that dynamically transform actual data into a virtual homogeneous database and allow client applications to query it. The InterDB approach provides a complete methodology to define this architecture, including schema recovery through reverse engineering, database integration and mapping building. The methodology is supported by the DB-MAIN CASE tool that helps developers generate the mediators and their repository.

Accessing and managing data from several existing independent databases pose complex problems that can be classified into platform, DMS, location and semantic levels. This paper describes a general architecture, a methodology and a CASE environment intended to address the problem of providing users and programmers with an abstract interface to independent heterogeneous and distributed databases. The architecture comprises a hierarchy of mediators that dynamically transform actual data into a virtual homogeneous database. Each layer provides a certain kind of independence. The InterDB approach provides a complete methodology to define this architecture, including schema recovery through reverse engineering, database integration and mapping building. The methodology is supported by the DB-MAIN CASE tool that helps to generate the mediators and their repository.