Semantic Web. SPARQL By Example (1) XQuery/SPARQL Tutorial - Wikibooks, collection of open-content textbooks. SPARQL interface The emp-dept RDF can be queried using SPARQL via an XQuery front end to a store provided by Talis.
This script supports SPARQL queries and browsing the RDF graph. The interface expands a query like that you can run here into and sends this to the Talis service in a form that can be run that you can run here. Example Queries List all employees Run List the names of all employees in alphabetical order Run List the employees' name, salary, department number and job Note that ; in place of . repeats the subject.
Try out this and the following queries here. List the first 5 employees List the top 5 employees by salary List the departments List all departments and all employees List the employees with salaries over 1000 If the RDF literal is typed, for example as xs:integer as is the case with this generated RDF, then the following query will select employees with a salary greater than 1000: List employees and their locations ESWC 2007 Tutorial: SPARQL - Where are we? Current state, theory and practice. Marcelo Arenas Claudio Gutierrez Bijan Parsia Jorge Pérez Axel Polleres Andy Seaborne Supported by FONDECYT grants 1070732, 1070348, CWR project P04-067-F, EU FP6 project inContext IST-034718, MEC/URJC project SWOS URJC-CM-2006-CET-0300.
Unit 1Unit 2Unit 3Unit 4Unit 5Unit 6 Handout booklet (PDF) After the data and ontology layers of the Semantic Web stack have achieved considerable stability through standard recommendations such as RDF and OWL, the query layer is the next item to be completed on W3C's agenda. This is just the right moment to reflect on the current state of the language and its applications, which we aim to provide in the proposed tutorial.
The presenters of this tutorial tackle the topic of Semantic Web querying and SPARQL from various, complementary viewpoints. The first part of the tutorial will have emphasis in providing a solid basis in the semantics and use of the language. Unit 1 - SPARQL Basics (90min) Material: Slides Unit 1 (PDF) Unit 2 - SPARQL Semantics (45min) A crash course in SPARQL - Data-gov Wiki. From Data-gov Wiki 1.
Introduction SPARQL is a query language for the Semantic Web. It was designed to be similar to SQL, a query laguage for relational databases, so it is relatively easy for people to learn it. An examples of a query can be You can go to copy and paste the previous code into the box and click on "run query". The results are displayed in HTML form (there are other formats we will look later). 2. A Triple is the minimal amount of information expressable in Semantic Web. A subject which is a URI (e.g., a "web address") that represents something. Thus, for example, a few triples can be < "Alvaro" < . 3. Back to our first example, we can see now what it does. In english, we are asking "Give me some resource that has a title". 4. One of the problems with managing URIs is that they re too long. Introducing Linked Data And The Semantic Web.
Next: Introducing Graph Data What is Linked Data and the Semantic Web and what is all the hype about?
Principally, the Semantic Web is a Web 3.0 web technology - a way of linking data between systems or entities that allows for rich, self-describing interrelations of data available across the globe on the web. In essence, it marks a shift in thinking from publishing data in human readable HTML documents to machine readable documents. That means that machines can do a little more of the thinking work for us. How Does It Differ From The Web As It Is Today? Today, much of the data we get from the web is delivered to us in the form of web pages - HTML documents that are linked to each other through the use of hyperlinks. Enter Linked Data - Liberating Web Databases From Their Old Chains The web contains lots of information, but typically the raw data itself isn't available - rather only HTML documents constructed from data, if a web site is generated from a database at all. But Where Do I Start?