Author(s): Kārlis Čerāns, Uldis Bojars, Agris Sostaks, Juris Barzdins, Julija Ovcinnikova, Lelde Lace, Mikus Grasmanis, Arturs Sprogis
Abstract: Visual SPARQL query formulation notations aim at easing the RDF data querying task, still the existing approaches fall short of providing a generally accepted visual notation suitable for data analysis and statistics queries. In this paper we present a visual diagram-centered notation and tool for SPARQL select query formulation, capable to cover aggregate/statistics queries and hierarchic queries with subquery structure. We present the notation usage examples, describe its syntax structure and provide the semantics by defining the visual query translation into SPARQL. We report on early pilot studies indicating the potential applicability of the visual notation to formulating SPARQL queries, as well as briefly describe the web-based open source implementation of the tool.
Keywords: Visual notation; Diagrammatic queries; RDF data endpoints; SPARQL; Ad-hoc queries; Data analysis; Multi-modal query tool