> I'm not sure I completely understand the use case that this approach is > trying to address. But at best, it looks like a nonstandard, > application-specific shortcut to produce something like a table with > subrows.
Right now Jena returns 1 triple per line. For example - author-1 book-1 - author-1 book-2 - author-2 book-1 ... instead of - author-1 ---- book-1 ---- book-2 - author-2 ---- book-1 the nested structure (second one) looks much more natural in the context of graphs, like RDF. The first approach instead returns results like any other RDBMS. This is a problem because even if it's true that traversing a graph with SPARQL is very easy (something that would require a huge number of JOINs in SQL), the returned data grows exponentially, in particular if you are following several predicate links and want to return properties from nodes in between. For every different value a new row is added to the results, so the number of results is like "property1 x property2 x property3 x ..."
