The RDF Query Language (RQL)

RQL is a typed language following a functional approach (a la ODMG-OQL) and supports generalized path expressions (GPEs) featuring variables on both labels for nodes (i.e., classes) and edges (i.e., properties). RQL relies on a formal graph model (as opposed to other triple-based RDF QLs ) that captures the RDF modeling primitives and permits the interpretation of superimposed resource descriptions by means of one or more schemas.

http://139.91.183.30:9090/RDF/RQL/