RDF+OWL to Relational Mapping + OBDA Access

1. Mapping of RDF data according to an OWL ontology to the relational model and store it in a relational database.
2. Populate the database from RDF tuples.
3. Queries can then be stated either in SQL, or in SPARQL which is automatically translated to SQL.

The prototype implementation RDF2SQL can be found here.
Note: to play with the prototype, first run the "init" button to create a new database - parts of it are in-memory of the Web Service instantiation, which is destroyed when it is not used.

Draft Technical Report:

• Draft Technical Report (subject to change)

Input Files:

• mondial-meta.n3 The Ontology
• mondial.n3 Individuals and their properties
• mondial-europe.n3
• mondial-er.n3 Declaration of AnnotationProperties etc in the er: namespace to configure the mapping

• The first steps dealing with the extracting of concise ER-style information from an OWL ontology date back to our OWLED-2013 paper. Note that it is not easy to query an ontology to find out what properties are functional on certain subsets of its domain.
• RDF2SQL has been used in the RODI Benchmark to generate variants of the Mondial database.
• The paper Systematical Representation of RDF-to-Relational Mappings for Ontology-Based Data Access appeared at OTM 2017.