QLever
Original author(s) | Hannah Bast, Björn Buchhold, Johannes Kalmbach, et al.[1][2] |
---|---|
Initial release | 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.[1] A specialized user interface for QLever predictively autocompletes SPARQL queries.[2]
Characteristics
[edit]A 2023 study compared QLever with Virtuoso, Blazegraph, GraphDB, Stardog, Apache Jena, and Oxigraph. The QLever version investigated in the study achieved fast execution of successful queries but offered limited support for complex SPARQL constructs.[3]
Contents
[edit]The official QLever instance provides API endpoints for querying the following datasets:[4]
- Wikidata
- Wikimedia Commons
- Freebase
- OpenStreetMap
- OpenHistoricalMap
- UniProt
- PubChem
- DBLP
- OpenCitations
- IMDb
- Integrated Authority File
- YAGO
- DBpedia
- Wallscope Olympics database
For OpenStreetMap and OpenHistoricalMap data, the QLever engine supports a limited subset of GeoSPARQL functions, supplemented by a precomputed subset of GeoSPARQL relationships stored as dedicated triples.[5]
Adoption
[edit]Besides the official instance, the QLever engine also powers the official SPARQL endpoint of DBLP.[6] QLever is one of the candidates to replace Blazegraph as the triplestore for the Wikidata Query Service.[3]
See also
[edit]References
[edit]- ^ a b Bast & Buchhold 2017.
- ^ a b Bast et al. 2021.
- ^ a b Lam, An Ngoc; Elvesæter, Brian; Martin-Recuerda, Francisco (2023). Evaluation of a Representative Selection of SPARQL Query Engines Using Wikidata (PDF). Extended Semantic Web Conference. Lecture Notes in Computer Science. Vol. 13870. Springer, Cham. doi:10.1007/978-3-031-33455-9_40.
- ^ "QLever". Freiburg im Breisgau: University of Freiburg Chair for Algorithms and Data Structures. Retrieved 13 July 2024.
- ^ Bast et al. 2021.
- ^ "dblp SPARQL query service". Schloss Dagstuhl. Retrieved 2024-11-09.
Further reading
[edit]- 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 [cs.DB].