RDF is designed to be a data store. It follows that as soon as RDF came out, people wanted a way to query, like a traditional database. SPARQL is a new RDF query language that has recently become a W3C recommendation. You can think of SPARQL as writing a query, loosely akin to SQL for databases, to parse an XML file, specifically an RDF file. The results returned to you are row and column tables just like in SQL.
Most people learned SQL with the aid of a command line client that queried a database. This allowed us to experiment and play with query structures. Fortunately for SPARQL, there is something similar; SPARQLer, located at http://www.sparql.org/sparql.html, is an interactive web tool that allows you to specify an RDF document on the web as an input and write SPARQL queries against it. It will display the query results to us much like the results from a database client. As we go through our initial discussion of SPARQL, we will use this query tool and an example document RDF...