Hi, Sören -- On Jul 14, 2010, at 07:55 AM, Sören Auer wrote: > For some experiments we plan to run it would be very useful to > embed an SQL query as a subquery inside a SPARQL query. We want > to combine relational with RDF data for example in the following > way:
While not exactly what you're asking for, this may be sufficient for what you want to achieve -- <http://docs.openlinksw.com/virtuoso/rdfsparql.html#rdfsqlfromsparql> > 16.2.10. Calling SQL from SPARQL > > A SPARQL expression can contain calls to Virtuoso/PL functions and > built-in SQL functions in both the WHERE clause and in the result > set. Two namespace prefixes, bif and sql are reserved for these > purposes. When a function name starts with the bif: namespace prefix, > the rest of the name is treated as the name of a SQL BIF (Built-In > Function). When a function name starts with the sql: namespace prefix, > the rest of the name is treated as the name of a Virtuoso/PL function > owned by DBA with database qualifier DB, e.g. sql:example(...) is > converted into DB.DBA."example"(...). > > In both cases, the function receives arguments in SQL format ('SQL > valmode') and also returns the result in SQL format. The SPARQL > compiler will automatically add code for format conversion into > the resulting SQL code so SQL functions can be used even if define > output:valmode 'LONG' forces the use of RDF representation in the > result set. Be seeing you, Ted -- A: Yes. http://www.guckes.net/faq/attribution.html | Q: Are you sure? | | A: Because it reverses the logical flow of conversation. | | | Q: Why is top posting frowned upon? Ted Thibodeau, Jr. // voice +1-781-273-0900 x32 Evangelism & Support // mailto:[email protected] // http://twitter.com/TallTed OpenLink Software, Inc. // http://www.openlinksw.com/ 10 Burlington Mall Road, Suite 265, Burlington MA 01803 http://www.openlinksw.com/weblogs/uda/ OpenLink Blogs http://www.openlinksw.com/weblogs/virtuoso/ http://www.openlinksw.com/blog/~kidehen/ Universal Data Access and Virtual Database Technology Providers
