Using SPARQL to access Linked Open Data. Lesson Goals This lesson explains why many cultural institutions are adopting graph databases, and how researchers can access these data though the query language called SPARQL.
Table of contents Many cultural institutions now offer access to their collections information through web Application Programming Interfaces. While these APIs are a powerful way to access individual records in a machine-readable manner, they are not ideal for cultural heritage data because they are structured to work for a predetermined set of queries. For example, a museum may have information on donors, artists, artworks, exhibitions, and provenance, but its web API may offer only object-wise retrieval, making it difficult or impossible to search for associated data about donors, artists, provenance, etc. RDF databases are well-suited to expressing complex relationships between many entities, like people, places, events, and concepts tied to individual objects.
RDF in brief. Vapour, a Linked Data validator. SparqlImplementations. This page lists some implementations of SPARQL, a query language and protocol for RDF acccess released by the W3C RDF Data Access Working Group - DAWG.
SPARQL query language spec SPARQL Protocol spec SPARQL XML results spec SPARQL Implementation Survey See DawgShows for online demos and services. Client Side. YASGUI. NeXtProt SnorQL. What happens if one endpoint fails in federated query. Uk-bnb provided by the Talis Platform. Revisiting Blank Nodes in RDF to Avoid the Semantic Mismatch with SPARQL. WED 730 Wallace 3780. If statement - Binding a variable to one of two values with IF? Linked Data Fragments. Wikibase/Indexing/SPARQL Query Examples. Syntax according to RDF Dump format.
See also Further examples can be found at d:Wikidata:SPARQL query service/queries This page is parsed by the web interface of the query service to fill its drop down of example queries. Keywords in the line below the header are used to be populate the keyword cloud. Consider adding a comment in the query noting what it illustrates, when and by whom it was written and which are its limitations given the current data and use of properties at Wikidata. WDQ queries: Standard Prefixes These are standard prefixes, however their use is optional as the query endpoint knows to resolve standard prefixes automatically. Wikidata Query Service (Beta)
Normalizing company names with SPARQL and DBpedia. The query below can be run with any SPARQL client that supports 1.1.
I wanted it to cover these three cases: Run it with an unofficial company name such as Big Blue, Apple Computer, or Kodak, and it should return the official company name.Run it with an official company name such as IBM, Apple, Inc., or Eastman Kodak, and it should return that name. Run it with something that isn't a company, such as Snee, and it shouldn't return anything. The query's first BIND statement sets the name to check (including a language tag, because DBpedia is pretty consistent about using those) in the ? InputName variable, and the SERVICE keyword sends the bolded part of the query off to DBpedia's SPARQL endpoint. SEMAKU — Using COALESCE and IF in SPARQL for nested... For a current project we need to load data from an RDF graph store to populate tables in an existing SQL database.
The approach we chose is to use SPARQL SELECT queries to express the mapping from the graph to tabular model. The CSV results from such a query can be used to populate the tables in the target database. One of the columns in the target table contains coded values, where each code indicates the ‘type’ of the thing the row describes. The codes are two or three letters (e.g. FE, FA, NMF) where each code has a predetermined meaning. However the RDF data used more types than in the target database, so it was necessary to create an n:1 mapping. Rdf - Populating an OWL ontology from external SPARQL endpoints. Jena - Is there any free owl reasoner that can reason without load all data into memory? Reasoning and SPARQL through ARQ command line.
I'm just getting started with ontologies, so forgive me if I'm missing something blatantly obvious here.
I've been experimenting with Protégé, setting up a simple ontology. Among other things, I've got ? X knows ? Y triples, where knows is a symmetric relationship. Vocabulary of Interlinked Datasets (VoID) Sparql Services. The datasets are available as linked data - that is in RDF (Resource Description Framework).
If you want to directly access this data you can use the SPARQL endpoints that we are exposing. SPARQL is a query language for RDF. Full details on SPARQL can be found on the W3C website at (If you would like to access the data but SPARQL isn't your thing have a look at the APIs page.) Getting Started With Querying Using SPARQL Currently there are endpoints for the following datasets: If you follow the links above you will find some more information on how to query the individual datasets and some sample queries, along with sandboxes to try out your own queries. Results Formats. Datasets. A list of datasets is given below.
To find out more about what is in those datasets and how to access them follow the links. Underpinning the datasets is our RDF store - 5Store. 5Store is the very latest software from Garlik and is built upon the experience of their earlier open source versions such as 4Store. 5Store takes the capabilities of RDF stores to the next level, being capable of storing up to 1 trillion triples and providing scalability through an extensible cluster design. 5Store is itself under active development with Garlik and their partners, such as TSO, constantly monitoring changes in RDF store technologies and updating the software as applicable.
The British National Bibliography. Accessing the British National Bibliography Using SPARQL – Lost Boy. This is the third in a series of posts (1, 2, 3, 4) providing background and tutorial material about the British National Bibliography.
The tutorials were written as part of some freelance work I did for the British Library at the end of 2012. The material was used as input to creating the new documentation for their Linked Data platform but hasn’t been otherwise published. They are now published here with permission of the BL. Note: while I’ve attempted to fix up these instructions to account with changes to the platform on which the data is published, there may still be some errors. If there are then please leave a comment or drop me an email and I’ll endeavour to fix. The British National Bibliography (BNB) is a bibliographic database that contains data on a wide range of books and serial publications published in the UK and Ireland since the 1950s. The tutorial introduces developers to the BNB API which supports querying of the dataset via the SPARQL query language and protocol.
Managing RDF Using Named Graphs. [protege-owl] Tutorial for using SPARQL with OWL. Tools. The OpenUp Client makes use of several features of OpenUp that we're working on, including the Data Enrichment Service (DES) and the RDF store.
We wanted to experiment with things like web page extraction, what CORS can give you and performance of an application such as this. So, for now, it is just an experiment! A Narrative for Understanding SPARQL’s: FROM, FROM NAMED and GRAPH. When I first began learning SPARQL, I was fortunate enough not to have to try and tackle the named graphs concept of RDF and SPARQL at the same time. My queries were fully limited to the default graph and I had some time to learn queries in SPARQL before attempting to move on. In fact, in those days there were very limited educational resources on either RDF or SPARQL, and I learned mostly by example. But then I had need to tackle named graphs and I can recall just how difficult it was to gain an understanding of how the SPARQL constructs for working with named graphs work.
Later, as I joined Cray and also became active on “Semantic Overflow” (which now exists as the Q&A board at semanticweb.com, I realized that very many smart people also struggle with the concept for some time before they come to grips. RDFS, Jena: how to query taking ontology into account. SPARQL query RDF ontology. How to query Classes with Object Property in Sparql - JJask.com. How to query Classes with Object Property in Sparql - JJask.com. Difference between domain and range in rdf schema? Can we combine CONSTRUCT with aggregates in SPARQL 1.1? SPARQL tips and tricks. This section describes SPARQL patterns that are frequently used for managing, understanding, and analyzing data. For example, this topic provides details about how to delete all data associated with an object and how to perform a cascaded delete. It also provides tips for understanding your data as a graph by analyzing social networks to find the most connected people and the size of their network out to one or two degrees.
Tips and tricks for managing your data How do I find all of the triples that reference a resource? A common task is to find all of the triples in a graph that refer to a particular resource. To find all of the triples that reference person2, the following example query returns all of the triples where person2 is the subject or object:
SPARQL — Personal Wiki. In Semantic Web, SPARQL is a query language for getting information from RDF graphs SPARQL = SPARQL Protocol and RDF Query Language matches graph patterns - so also a graph matching language it's a variant of Turtle adapted for querying variables denoted by ? Formal foundation Versions Basic Things Aggregations Negations Nested Queries Transitive Properties. Learn about SPARQL 1.1. David Beckett This presentation is personal opinion. I am not speaking on behalf of my employer, Digg Inc.. The slides are presented via S5. RDF Validator. Putting WorldCat Data Into A Triple Store. By Richard Wallis on August 21, 2012 - 14 Comments Published in Consuming Data, Data Publishing, Libraries, Linked Data, OCLCTagged: 4Store, Linked Data, OCLC, RDF, SPARQL, WorldCat I can not really get away with making a statement like “Better still, download and install a triplestore [such as 4Store], load up the approximately 80 million triples and practice some SPARQL on them” and then not following it up.
I made it in my previous post Get Yourself a Linked Data Piece of WorldCat to Play With in which I was highlighting the release of a download file containing RDF descriptions of the 1.2 million most highly held resources in WorldCat.org – to make the cut, a resource had to be held by more than 250 libraries. Semantic Web Practice - Other SPARQL Query Forms (CONSTRUCT, ASK, DESCRIBE) 1. SPARQL Query Examples - Knowledge Wiki - Base22 Wiki. SPARQL Query Examples - Knowledge Wiki - Base22 Wiki. AllegroGraph 4.14.1. Introduction This is not a semantics document, or a general description of SPARQL, or a standards document; for these, we advise the reader to look elsewhere, starting with the SPARQL Reference. Note that this document sometimes omits details or complicating factors, entirely or until later. The tutorial uses the AGWebView client for AllegroGraph (see WebView). To run this tutorial, start an AllegroGraph server and log into AllegroGraph WebView with your browser.
SPARQL Cheat Sheet. Er. SparklePrettyPrinterV4 - sparkle-g - SPARKLE-G Pretty Printer and Syntactic Validator for SPARQL built on ANTLR V4 - The SPARQL (pron: sparkle) query language ANTLR4 Grammar. Table of Content. 4store - Scalable RDF storage. Loading the British National Bibliography into an RDF Database. This is the second in a series of posts (1, 2, 3, 4) providing background and tutorial material about the British National Bibliography. How to install Jena Fuseki - TheInfoHunger. In this tutorial i will teach you how to install the Jena Fuseki server in the windows machine. Fuseki – it really is that easy! Fuseki is part of the Apache Jena project, but is distributed as a separate package. Fuseki is an HTTP server with all the Jena modules hooked together inside its belly. SparqlImplementations - W3C Wiki. Milan Markovic - Guides:How to.
Query Form - SPARQL Endpoint - Revyu.com. The British National Bibliography. GeoSPARQL. GeoSPARQL - A Geographic Query Language for RDF Data. SPARQL 1.1 Query Language. Home.