Valet SADI: Provisioning SADI Web Services for Semantic Querying of Relational Databases

Semantic Querying (SQ) is emerging as an attractive approach for retrieval of data from relational and other conceptually similar databases, targeting users with limited or no technical expertise. Using SQ queries can be formulated using terminologies from a specific domain, which are then either translated in real time into the equivalent SQL queries, or executed against a materialised semantic database obtained by transforming the source relational data. This approach is suitable for non-technical users who are familiar with describing a domain using the terminologies in an ontology but lack expertise in writing SQL queries over complex relational schemas. As an alternative to the existing methods, we implement the vision of SQ on relational databases by deploying Semantic Web services over one or more databases and querying them with SPARQL queries. The approach based on manual Semantic Web service writing under-utilises easily manageable declarative mappings between source data schemas and domain ontologies. In this paper we introduce the Valet SADI framework to automate the creation of SADI Semantic Web services from declarative mappings, and demonstrate that Valet SADI, together with SADI query engines, establishes semantic querying as a viable, economical and user friendly way of querying relational databases.