| Original author(s) | Hannah Bast, Björn Buchhold, et al. |
|---|---|
| Initial release | 2017; 8 years ago (2017) |
| Repository | github |
| Written in | C++ |
| Standard(s) | SPARQL |
| Available in | English |
| Type | Graph database |
| License | Apache License |
| Website | qlever |
QLever (pronounced /ˈklɛvər/ KLEH-ver, as in "clever") is an open-source triplestore and graph database developed by a team at the University of Freiburg led by Hannah Bast. QLever performs high-performance queries of semantic Web knowledge bases, including full-text search within text corpuses. A specialized user interface for QLever predictively autocompletes SPARQL queries.
QLever is one of the candidates to replace Blazegraph as the triplestore for the Wikidata Query Service. A 2023 study found that, compared to other triplestores, QLever achieved fast execution of successful queries but offered limited support for complex SPARQL constructs.
Contents
The official QLever server provides access to the following datasets:
- Wikidata
- Wikimedia Commons
- Freebase
- OpenStreetMap
- OpenHistoricalMap
- UniProt
- PubChem
- DBLP
- OpenCitations
- IMDb
- Integrated Authority File
- YAGO
- DBpedia
- Wallscope Olympics database
Although the QLever engine lacks support for GeoSPARQL functions per se, the official server precomputes a subset of GeoSPARQL relationships into dedicated triples for OpenStreetMap and OpenHistoricalMap data.
See also
References
- ^ Bast & Buchhold 2017.
- Bast et al. 2021.
- Lam, An Ngoc; Elvesæter, Brian; Martin-Recuerda, Francisco (2023). Evaluation of a Representative Selection of SPARQL Query Engines Using Wikidata. Extended Semantic Web Conference. Lecture Notes in Computer Science. Vol. 13870. Springer, Cham – via SpringerLink.
- "QLever". Freiburg im Breisgau: University of Freiburg Chair for Algorithms and Data Structures. Retrieved 13 July 2024.
- Bast et al. 2021.
Further reading
- Bast, Hannah; Brosi, Patrick; Kalmbach, Johannes; Lehmann, Axel (November 2–5, 2021). An Efficient RDF Converter and SPARQL Endpoint for the Complete OpenStreetMap Data (PDF). SIGSPATIAL. Beijing: Association for Computing Machinery. doi:10.1145/3474717.3484256. ISBN 978-1-4503-8664-7.
- Bast, Hannah; Buchhold, Björn (November 6–10, 2017). QLever: A Query Engine for Efficient SPARQL+Text Search (PDF). Conference on Information and Knowledge Management. Singapore: Association for Computing Machinery. doi:10.1145/3132847.3132921. ISBN 978-1-4503-4918-5.
- Bast, Hannah; Kalmbach, Johannes; Klumpp, Theresa; Kramer, Florian; Schnelle, Niklas (29 April 2021). "Efficient SPARQL Autocompletion via SPARQL". arXiv:2104.14595v1 .