A graph processing system that supports automatic data model conversion from Resource Framework Description (RDF) to Property Graph (PG) is provided. Rather than using a naive conversion approach that creates PG nodes and edges without properties, a set of conversion rules is evaluated to automatically convert RDF triples into PG nodes and edges with properties, as appropriate. Accordingly, the converted PG data takes full advantage of the PG format while advantageously avoiding the creation of extraneous nodes and edges, allowing queries on the PG data to be efficiently executed on any database supporting the PG data model. The plurality of rules categorize each triple into three different cases depending on whether or not the predicate is “rdf:type” and whether or not the object is a literal value, generating graph entities as appropriate for each case. Optionally, user defined rules may override the automatic rules.