Enhanced Regular Path Queries on Semistructured Databases

Abstract. Regular path queries are the basic navigational component of virtually all the mechanisms for querying semistructured data commonly found in information integration applications, Web and communication networks, biological data management etc. We start by proposing weight-enhanced regular path queries with semantics that allow user-assigned preference (query) weights to be naturally combined with quantitative database link-information for driving the navigation. Motivated by the fact that the main applications of semistructured data involve distributed data sources, we focus next on the distributed eval-uation of the weight-enhanced path queries. We present a distributed algorithm for evaluating our proposed queries in a multi-source setting. Our algorithm is general in the sense that it does not assume a known topology of the network and it can work using asynchronous communi-cation. This algorithm can also be used to solve multi-source shortest path problems for which the full graph is not known in advance. To the best of our knowledge our algorithm is the first to address this problem in such a setting.