[Virtuoso-users] SQL subquery embedded in a SPARQL query

[Sören Auer]

Hi,

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:

Lets assume we have foaf profiles in the triple store and a relational 
table with information about people (e.g. from a CRM system). A query 
similar to the following would be really useful in that case:

PREFIX : <http://people.example/>
SELECT ?y ?name ?age WHERE {
  :alice :knows ?y .
  {
    SQL SELECT y, name, age FROM people
  }
}

Instead of joining with the triple table a join with the SQL subquery 
would occur and SPARQL variables would be matched against columns of the 
SQL result set with the same name.

Does this make sense? Are there already plans to implement something 
along these lines in Virtuoso? I think this functionality would 
dramatically simplify a number of data integration tasks and be a 
wonderful USP for Virtuoso.

Best,

Sören