RML Playground: Online Editing, Validation, and Execution for the RDF Mapping Language

Els de Vleeschauwer, Arthur Vercruysse, Ben De Meester, Pieter Colpaert

Keywords: Knowledge Graph Construction, Playground, RDF Mapping Language, Semantic Web Language Server

TL;DR: We demonstrate RML Playground, a Web application that allows end-users to create, edit, and execute qualitative RML mapping rules in various dialects.

Abstract: The RDF Mapping Language (RML) has seen various extensions over the years and was overhauled and modularized by the W3C KGC Community Group. However, this variety of RML versions and varying support for varying features by different mapping engines makes it hard for end-users to know how to create valid mapping rules. We demonstrate RML Playground: a Web application available at https://w3id.org/imec/rml/playground that guides end-users to edit, validate, and execute valid mapping rules in multiple variations. The RML Playground offers (i) a text editor with real-time RDF syntax and SHACL shape validation and autocompletion, powered by the Semantic Web Language Server (SWLS); (ii) a KG construction pipeline using a configurable mapping engine; and (iii) curated example mapping rules illustrating the targeted RML variation. RML Playground is currently deployed in two variations: the latest KGC Community RML version with Burp as mapping engine, and the RML.io-published RML version with RMLMapper as mapping engine. Completely automated using the specifications’ ontology and shape descriptions, the RML Playground is easily extensible and maintainable to new RML versions and extensions. Its use of the specifications’ documentation allows editors to validate their correctness, and the provision of meaningful hints during the editing process lowers the barrier for using the (new) RML specifications and can be used during training and dissemination activities.

Submission Number: 5