Metadata Based Mediator Generation
Terence Critchlow, Madhavan Ganesh, Ron Musick
Center for Applied Scientific Computing
Lawrence Livermore National Laboratory
P.O. Box 808, L-561, Livermore, CA 94551
{critchlow | ganesh | rmusick}@llnl.gov
Abstract
Mediators are a critical component of any data warehouse, particularly
one utilizing partially materialized views; they transform data from
its source format to the warehouse representation while resolving
semantic and syntactic conflicts. The close relationship between
mediators and databases requires a mediator to be updated whenever an
associated schema is modified. This maintenance may be a significant
undertaking if a warehouse integrates several dynamic data sources.
However, failure to quickly perform these updates significantly
reduces the reliability of the warehouse because queries do not have
access to the most current data. This may result in incorrect of
misleading responses, and reduce user confidence in the warehouse.
This paper describes a metadata framework, and associated software,
designed to automate a significant portion of the mediator generation
task and thereby reduce the effort involved in adapting to schema
changes. By allowing the DBA to concentrate on identifying the
modifications at a high level, instead of reprogramming the mediator,
turnaround time is reduced and warehouse reliability is improved.
Appeared in
Proceedings of the Third IFCIS Conference on Cooperative Information Systems (CoopIS'98),
New York, NY. August 1998.