From legacy relational databases to the semantic web, the China Academy of Traditional Chinese Medicine (CATCM), where over 70 legacy relational databases are semantically interconnected by an ontology with over 70 classes and 800 properties, providing in
K. Cheung, H. Frost, M. Marshall, E. Prud'hommeaux, M. Samwald, J. Zhao, и A. Paschke. BMC Bioinformatics, (2009)"We have explored a tool called "FeDeRate", which enables a global SPARQL query to be decomposed into subqueries against the remote databases offering either SPARQL or SQL query interfaces.".
T. Green, G. Karvounarakis, и V. Tannen. PODS '07: Proceedings of the twenty-sixth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems, стр. 31--40. New York, NY, USA, ACM, (2007)