Direct Mappings between RDF and Property Graph Databases

Resource Description Framework (RDF) triplestores and Property Graph (PG) database systems are two approaches for data management that are based on modeling, storing and querying graph-like data. Given the heterogeneity between these systems, it becomes necessary to develop methods to allow interoperability among them. While there exist some approaches to exchange data and schema between RDF and PG databases, they lack compatibility and even a solid formal foundation. In this paper, we study the semantic interoperability between RDF and PG databases. Specifically, we present two direct mappings (schema-dependent and schema-independent) for transforming an RDF database into a PG database. We show that the proposed mappings possess the fundamental properties of semantics preservation and information preservation. The existence of both mappings allows us to conclude that the PG data model subsumes the expressiveness or information capacity of the RDF data model.