This lesson compares the SPARQL and SQL query languages, which are designed to query RDF and relational data, respectively. It is designed for those who know one and want to learn the other or who need to make some decisions about which to use for some purpose. In keeping with the culture of re-use and integration that pervades the Semantic Web, SPARQL can be used to access relational data as well as RDF. This lesson also briefly mentions two recent specifications for mapping between the two types of data models.
Keywords: SPARQL, SQL, R2RML, RDBMS
Publisher: Cambridge Semantics
Time required: P15M
Educational use: instruction
Interactivity type: expositive
- Formulates advanced queries on a remote SPARQL endpoint using the SERVICE directive.
- Knows methods such as Direct Mapping of Relational Data to RDF (2012) for transforming data from the relational model (keys, values, rows, columns, tables) into RDF graphs.
- Understands how to combine and filter graph patterns using operators such as UNION, OPTIONAL, FILTER, and MINUS.
- Understands the difference between SQL query language (which operates on database tables) and SPARQL (which operates on RDF graphs).
- Uses FROM to formulate queries with URLs and local files.