- From: Enrico Franconi <franconi@inf.unibz.it>
- Date: Sat, 21 May 2011 19:53:02 +0200
- To: Richard Cyganiak <richard@cyganiak.de>
- Cc: W3C RDB2RDF <public-rdb2rdf-wg@w3.org>
A slightly more expressive but very interesting case would be relational combinations of CQs (namely union, intersection, difference of CQs). --e. On 21 May 2011, at 16:40, Enrico Franconi wrote: > Personally I believe that is is already an achievement to cover conjunctive queries, namely select-project-join / positive select-from-where (SQL) and BGPs (SPARQL). > > On 21 May 2011, at 16:23, Richard Cyganiak <richard@cyganiak.de> wrote: > >> On 20 May 2011, at 23:04, Enrico Franconi wrote: >>>> Your argument hinges on a claim that one proposal is correct, and another is incorrect. Can you state the criteria that an RDB2RDF mapping has to fulfill so that you consider it correct and complete? >>> >>> As I say in the wiki, I consider the query answering (QA) problem. A translation from data and queries in RDB/SQL to RDF/SPARQL is sound whenever any tuple returned in the translated QA problem is also returned in the original QA problem; it is complete if any tuple returned in the original QA problem is also returned in the translated QA problem. >> >> What expressivity of queries does the translation of queries have to cover? SPARQL, SQL or something else? >> >> Thanks, >> Richard >
Received on Saturday, 21 May 2011 17:53:32 UTC