Approximate querying of XML fuzzy data

The MIEL++ system integrates data expressed in two different formalisms: a relational database and an XML database. The XML database is filled with data semi-automatically retrieved from the Web, which have been semantically enriched according to the ontology used in the relational database. These data may be imprecise and represented as possibility distributions. The MIEL++ querying system scans the two databases simultaneously in a transparent way for the end-user. To scan the XML database, the MIEL query is translated into an XML tree query. In this paper, we propose to introduce flexibility into the query processing of the XML database, in order to take into account the imperfections due to the semantic enrichment of its data. This flexibility relies on fuzzy queries and query rewriting which consists in generating a set of approximate queries from an original query using three transformation techniques: deletion, renaming and insertion of query nodes.