Supporting structured, semi-structured and unstructured data in digital libraries

This work presents an approach to the design of digital libraries by raising and addressing issues involved in supporting services for collections of structured, semi-structured and unstructured objects. We present a system architecture for a digital library that includes provisions for storing and retrieving data with differing structure levels (ranging from highly unstructured to highly structured). We have successfully instantiated this architecture via a practical implementation that integrates technologies such as relational and novel XML databases as well as indexing and information retrieval techniques. A number of digital library applications are using these facilities for handling differing structure levels in an integrated fashion.