  This paper examines how a "Distributed Heterogeneous Relational Data
Warehouse" can be integrated in a Grid environment that will provide physicists
with efficient access to large and small object collections drawn from
databases at multiple sites. This paper investigates the requirements of
Grid-enabling such a warehouse, and explores how these requirements may be met
by extensions to existing Grid middleware. We present initial results obtained
with a working prototype warehouse of this kind using both SQLServer and
Oracle9i, where a Grid-enabled web-services interface makes it easier for
web-applications to access the distributed contents of the databases securely.
Based on the success of the prototype, we proposes a framework for using
heterogeneous relational data warehouse through the web-service interface and
create a single "Virtual Database System" for users. The ability to
transparently access data in this way, as shown in prototype, is likely to be a
very powerful facility for HENP and other grid users wishing to collate and
analyze information distributed over Grid.
