VDBMS: A solution to integrating heterogeneous data sources

We have developed a multidatabase system prototype called virtual DBMS (VDBMS) that integrates DBMSs developed independently. The VDBMS addresses several research and engineering issues. It incorporates schema integration, global query processing/optimization, global transaction processing, data dictionary management, and security enforcement. This paper describes our experience in the design and implementation of the VDBMS. We also discuss the design choices of various components of the VDBMS and the performance bottleneck we observed in the prototype. We believe these lessons are essential for practitioners as well as researchers to identity the important aspects of a multidatabase design.