So far, we’ve used the That was a lot of abstract text. Try to write a query that returns the ten most populous countries. (If you skipped the section about paths, skip this exercise too. English. Now you know how to search for all works of art, or all buildings, or all human settlements: the magic incantation Property paths are a way to very tersely write down a path of properties between two items. The code on line 2, after the hashtag sign, tells the query that the query results should be shown not as a table, but as a map. Suppose we want to list all children of the baroque composer Johann Sebastian Bach. The Wikidata Query Service provides a SPARQL endpoint including a powerful Web-GUI. )# no indentation; makes it hard to distinguish between ; and ,# French writer born in the second half of the 18th century# bind the pseudonym, or if it doesn’t exist the English label, as ?label )# (note: everything after a ‘#’ is a comment and ignored by WDQS. Suppose we’re not actually interested in Bach’s children. That sounds a bit awkward, doesn’t it? (The main challenge is finding the correct property…) (For good reason: “Johann Sebastian Bach” is also the name of a And last but not least, we need to include prefixes. In fact, it’s possible to express the same abbreviation in SPARQL as well: if you end a triple with a semicolon (which has the same results, but less repetition in the query. Fortunately, we’re allowed to use the new, aggregated variables from the What is the total number of guns produced by each manufacturer? In Wikidata, most properties are “has”-kind properties, so the query might instead read: SPARQL (pronounced “sparkle”) stands for “SPARQL Protocol and RDF Query Language”. The familiar mathematical operators are available: For example, to get a list of all humans born in 2015, we first get all humans with their date of birth – ... Wikidata also provides support to many other sites and services beyond just Wikimedia projects! Write a query that returns all books by Sir Arthur Conan Doyle. So far, we’ve only talked about simple statements: subject, property, object. Why is that? You can also write this as: While this guide may look very long and intimidating, please don’t let that scare you away! The path might include two mothers and one father, or four fathers, or father-mother-mother-father, or any other combination. On Wikidata, items and properties are not identified by human-readable names like “father” (property) or “Bach” (item). Instead, we might ask questions like this: # Sample to query all values of a property # Property talk pages on Wikidata include basic queries adapted to each property SELECT ?item ?itemLabel ?value ?valueLabel # valueLabel is only useful for properties with item-datatype WHERE { ?item wdt:P1800 ?value # change P1800 to another property SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }

Normally, we restrict results with a Here’s a short summary of the available aggregate functions: There’s so much potential data about books, and we only show the label? Introduction. Wikidata is a database of this type.This tutorial aims to give you a friendly introduction to SPARQL so you can learn to query Wikidata even if you have no background in writing queries or programming languages.

If it has some of those properties, but not all of them, it won’t match. Primary Menu. Introduction. (Aren’t rhetorical questions great?) We return to our regular scheduled program of more SPARQL features. SPARQL (pronounced "sparkle") is an RDF query language, that is, a semantic query language for databases. The basic concept is that we would like to do something with the values that, so far, we’ve just selected and returned indiscriminately. Exercise: rewrite the “grandchildren of Bach” query from earlier to use this syntax. (Who knows, perhaps that’s actually true for you!) These queries retrieve date information making it possible to present this information in the form of a timeline. Since we’re ordering the results by country, all cities belonging to a country form one contiguous block in the results. Wikidata Query Service Tutorial. And that’s not what we want in this case: we primarily want a list of all the books – if additional data is available, we’d like to include it, but we don’t want that to limit our list of results. Right?) Let’s try to craft a query that also includes the Run that query. For simple WDQS triples, items should be prefixed with Putting this together, we arrive at our first proper WDQS query: Now I want to introduce one more abbreviation that SPARQL offers. Introduction to Wikidata; ... Take for example the query retrieving the number of tennis players on Wikidata. Okay, then onto the solution! Just learning the SPARQL basics will get you a long way – even if you stop reading after If you have never heard of Wikidata, SPARQL, or WDQS before, here’s a short explanation of those terms: So far, we’ve only had queries where we were interested in all results. SPARQL doesn’t: there’s still a lot that I haven’t shown you – I never promised this was going to be a complete guide!

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