The Rufus System: Information Organization for Semi-Structured Data

摘要

While database systems provide good function for writing applications on structured data, computer system users are inundated with a flood of semi-structured information, such as documents, electronic mail, programs, and images. Today, this information is typically stored in filesystems that provide limited support for organizing, searching, and operating upon this data. Current database systems are inappropriate for semi-structured information because they require that the data be translated to their data model, breaking all current applications that use the data. Although research in database systems has concentrated on extending them to handle more varieties of fully structured data, database systems provide important function that could help users of semi-structured information. The Rufus system attacks the problems of semi-structured data. It provides searching, organizing, and browsing for the semi-structured information commonly stored in computer systems. Rufus models information with an extensible object-oriented class hierarchy and provides automatic classification of user data within that hierarchy. Query access is provided to help users search for needed information. Various ways of structuring user information are provided to help users browse. Methods associated with Rufus classes encapsulate actions that users can take on the data. These capabilities are packaged in a framework for use by applications. We have built two demonstration applications using this framework: a generic search and browse application called xrufus and an extension to the Usenet news reading program trn. These applications are in daily use at our research laboratory. This paper describes the design and implementation of our framework, our experiences using it, and their influence on the next version of Rufus.