More and more people are using the query language SPARQL (pronounced “sparkle”) to pull data from a growing collection of public and private data. Whether this data is part of a semantic web project or an integration of two inventory databases on different platforms behind the same firewall, SPARQL is making it easier to access it. In the words of W3C Director and Web inventor Tim Berners-Lee, “Trying to use the Semantic Web without SPARQL is like trying to use a relational database without SQL.”

SPARQL was not designed to query relational data, but to query data conforming to the RDF data model. RDF-based data formats have not yet achieved the mainstream status that XML and relational databases have, but an increasing number of IT professionals are discovering that tools using the RDF data model let them expose diverse sets of data (including, as we’ll see, relational databases) with a common, standardized interface. Both open source and commercial software have become available with SPARQL support, so you don’t need to learn new programming language APIs to take advantage of these data sources. This data and tool availability has led to SPARQL letting people access a wide variety of public data and providing easier integration of data silos within an enterprise.

Although this book’s table of contents, glossary, and index let it serve as a reference guide when you want to look up the syntax of common SPARQL tasks, it’s not a complete reference guide—if it covered every corner case that might happen when you use strange combinations of different keywords, it would be a much longer book.