Integrating a Structured-Text Retrieval System with an Object-Oriented Database System

We describe the integration of a structured-text retrieval system (TextMachine) into an object-oriented database system (OpenODB). Our approach is a light-weight one, using the external function capability of the database system to encapsulate the text retrieval system as an external information source. Yet, we are able to provide a tight integration in the query language and processing; the user can access the text retrieval system using a standard database query language. The e cient and e ective retrieval of structured text performed by the text retrieval system is seamlessly combined with the rich modeling and general-purpose querying capabilities of the database system, resulting in an integrated system with querying power beyond those of the underlying systems. The integrated system also provides uniform access to textual data in the text retrieval system and structured data in the database system, thereby achieving information fusion. We discuss the design and implementation of our prototype system, and address issues such as the proper framework for external integration, the modeling of complex categorization and structure hierarchies of documents (under automatic document schema importation), and techniques to reduce the performance overhead of accessing an external source.