QLever
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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]
| 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 |
Characteristics
A 2023 study compared QLever with Virtuoso, Blazegraph, GraphDB, Stardog, Apache Jena, and Oxigraph. The study investigated a QLever version from 2021, concluding that it achieved fast execution of successful queries but offered limited support for complex SPARQL constructs.[3][4]
Contents
The official QLever instance provides API endpoints for querying the following datasets:[5]
- 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.[6]
Adoption
Besides the official instance, the QLever engine also powers the official SPARQL endpoint of DBLP.[7] QLever is one of the candidates to replace Blazegraph as the triplestore for the Wikidata Query Service.[3]
See also
Wikimedia Commons has media related to QLever.
References
Further reading
External links
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