Integrating heterogeneous distributed database system

This paper demonstrates various aspects of resolving possible data conflicts occurring in the database integration process. A general model of a Heterogeneous Distributed Database System (HDDBS) based on a relational data model is presented. We also discuss the problems of heterogeneous database integration and the principal user requirements, together with design and implementation issues. The HDDBS suppresses differences of DBMS, language, and data models among the databases and provides users with a unified global schema and a single high-level query language. There are three principal research goals of the paper. The first goal is to develop appropriate language constructs for accessing and integrating heterogeneous databases. The second goal is to discover effective global and local optimization techniques. The final goal is to design methods for handling incompatible data representations and inconsistent data.