Metacat: a schema-independent XML database system

The ecological sciences represent a challenging community from the perspective of scientific data management. Ecological data are collected by investigators who are spread out over a large geographic area and who use a wide variety of research protocols and data-handling techniques. The resulting heterogeneous data are stored in autonomous database systems that are dispersed throughout the ecological community. The Knowledge Network for Biocomplexity is seeking to address these issues through the use of structured metadata encoded in the Extensible Markup Language (XML). The main goal of this project has been to design and implement a schema-independent data storage system for XML which is called Metacat. Metacat uses a hybrid XML storage approach using a commercial relational DBMS back-end while still allowing any arbitrary XML document to be stored. This paper describes the Metacat XML data storage system and its relevance to scientific data management in the ecological sciences.