An overview and classification of mediated query systems

Multimedia technology, global information infrastructures and other developments allow users to access more and more information sources of various types. However, the “technical” availability alone (by means of networks, WWW, mail systems, databases, etc.) is not sufficient for making meaningful and advanced use of all information available on-line. Therefore, the problem of effectively and efficiently accessing and querying heterogeneous and distributed data sources is an important research direction. This paper aims at classifying existing approaches which can be used to query heterogeneous data sources. We consider one of the approaches — the mediated query approach — in more detail and provide a classification framework for it as well.