Integration of Legacy and Heterogeneous Databases

Accessing and managing data from several existing independent databases pose complex problems that can be classified into platform, DMS, location and semantic levels. The platform level copes with the fact that databases reside on different brands of hardware, under different operating systems, and interacting through various network protocols. Leveling these differences leads to platform independence. DMS level independence allows programmers to ignore the technical details of data implementation in a definite family of models. It can also hide the model that the DMS implements by providing a more abstract model. Location independence isolates the user from knowing where the data reside. Finally, semantic level independence solves the problem of multiple, replicated and conflicting representations of similar facts. The InterDB project proposes 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.