RocketRML - A NodeJS implementation of a use-case specific RML mapper
This work addresses a specific bottleneck for researchers and practitioners in the Linked Data domain by providing a more efficient tool for mapping real-life touristic data to schema.org, but it is incremental as it builds on existing RML frameworks with targeted improvements.
The authors tackled the problem of inefficient RML mapping for large XML and JSON files in touristic data by developing RocketRML, a NodeJS-based implementation that showed great potential for heavy mapping tasks with reasonable performance, though it has limitations in handling JOINs, Named Graphs, and non-XML/JSON inputs.
The creation of Linked Data from raw data sources is, in theory, no rocket science (pun intended). Depending on the nature of the input and the mapping technology in use, it can become a quite tedious task. For our work on mapping real-life touristic data to the schema.org vocabulary we used RML but soon encountered, that the existing Java mapper implementations reached their limits and were not sufficient for our use cases. In this paper we describe a new implementation of an RML mapper. Written with the JavaScript based NodeJS framework it performs quite well for our uses cases where we work with large XML and JSON files. The performance testing and the execution of the RML test cases have shown, that the implementation has great potential to perform heavy mapping tasks in reasonable time, but comes with some limitations regarding JOINs, Named Graphs and inputs other than XML and JSON - which is fine at the moment, due to the nature of the given use cases.