Semantic markup languages such as RDF (Resource Description Framework) [21] and OWL (Web Ontology Language) [25] are increasingly being used to externalize meta-data or ontologies about data, software and services in a declarative form. Such externalized descriptions in ontological format are used for purposes ranging from search and retrieval to information integration and to service composition [22, 26]. The barrier to more wide-spread use of ontologies for such applications is the lack of support in the currently available middleware stacks used in enterprise computing. This paper presents our work on developing an enterprise-scale ontology management system that will provide APIs and query languages, and scalability and performance that enterprise applications demand. We present a novel approach to representing ontologies in relational database tables to address the scalability and performance issues.