Wikidata:SPARQL dotazovací služba
Co je SPARQL
SPARQL (vyslovujeme „sparkle“) je dotazovací jazyk RDF, tj. sémantický dotazovací jazyk pro databáze. Od září 2015 Wikidata poskytují SPARQL koncový bod včetně výkonného webového grafického uživatelského rozhraní. Se SPARQL můžete extrahovat jakýkoli druh dat pomocí dotazu složeného z logických kombinací trojic.
- GUI SPARQL dotazovací služby je zde: https://query.wikidata.org
- SPARQL koncový bod: https://query.wikidata.org/bigdata/namespace/wdq/sparql?query={SPARQL}
Učíme se SPARQL
Nápověda
- Nápověda SPARQL dotazovací služby
- Wikidata:SPARQL query service/queries
- Queries from Wikidata status update weekly summaries
Ostatní materiály
- SPARQL in 11 minutes (video, English)
- SPARQL Tutorial at the Apache Jena website (English)
- 2016 SPARQL Workshop presented by the Wikimedia Foundation (English)
- Querying Wikidata with SPARQL for Absolute Beginners, 2-hour video tutorial (English)
- Wikidata:SPARQL tutorial (multiple languages)
- Query optimization
- Query limits
{{Item documentation}}and other generic queries templates
Interfacing
SPARQL queries can be submitted directly to the SPARQL endpoint with GET request to https://query.wikidata.org/bigdata/namespace/wdq/sparql?query={SPARQL} or the endpoint's alias https://query.wikidata.org/sparql?query={SPARQL}. The result is returned as XML by default, or as JSON if either the query parameter format=json or the header Accept: application/sparql-results+json are provided. See the user manual for more detailed information. RDF data can alternatively be accessed via a Linked Data Fragments[1] interface at https://query.wikidata.org/bigdata/ldf.
- R package WikidataQueryServiceR which queries the WDQS SPARQL endpoint and returns data.frames
- R script (https://gist.github.com/andrawaag/2b8c831ab4dd70b16cf2) that plots Wikidata content on a world map in R. (Andra Waagmeester, https://lists.wikimedia.org/pipermail/wikidata/2015-September/007080.html)
- Python example, how to make a plot of causes of death for U.S. Presidents
- An example of using SPARQLWrapper library to query WDQS in Python: https://people.wikimedia.org/~bearloga/notes/wdqs-python.html
- An example using the Apache Jena command line tools. (This is useful e.g. for very large SPARQL statements with +2000 lines which WDQS UI currently cannot handle properly because of the parsing, or e.g., for scripting a batch of queries to run every week (via cron) and report the results by email)
- https://wdq2sparql.toolforge.org/w2s.php Convert WDQ (previous tool to query Wikidata) queries syntax to SPARQL (by Stas Malyshev)
- Generate plots for results by cutting-and-pasting queries to http://demo.seco.tkk.fi/visu – some examples by User:Pyb: U.S. States by date of creation, Burial counts for Père Lachaise cemetery by year, Dates of birth of 2000 centenarians
Wikimedia SPARQL query services
| Human interface | Machine's endpoint | Description |
|---|---|---|
https://query.wikidata.org/sparql
|
Run SPARQL Queries upon the Wikidata Wikibase instance. Run, test, download the data as XML, JSON, CSV, or TSV. Has advanced user-friendly features such as: word hovering to see a term's meaning, code optimization, etc. | |
https://commons-query.wikimedia.org/sparql
|
Run SPARQL Queries upon the Wikimedia Commons Wikibase instance. | |
https://lingualibre.org/sparql
|
Run SPARQL Queries upon the LinguaLibre Wikibase instance. Run, test, download the data as XML, JSON, CSV, or TSV. |
Statistiky
Další informace
- Special:ListDatatypes - covers approximate prefixes and explanation of some values
- Help:Dates - additional notes about dates
- Wikidata:SPARQL query service/Documentation - a hub for documents about the WDQS, organized under the Diátaxis framework
- SPARQL 1.1 W3C Recommendation
- Blazegraph wiki - Blazegraph is the query engine used by the Wikidata SPARQL query service. The wiki provides useful insights.
- Alternative endpoints