If a store has an index on my:hasUserID (and that index happens to be
in SPARQL's defined order!) then results can be generated in ordered
sequence.
Do you mean, I can assume to get "ordered" results without explicit
"ORDER BY" in the query, given the appropriate index? independent from
the database implementation? In my current setting (Sesame with
NativeStore - default index spoc, posc) this is not the case.
You can't assume anything about result order without including an ORDER BY clause for each column you care about. I was
simply commenting on the relative expense of a query: an implementation with the right predicate-specific index (and a
sufficiently smart planner) would -- in principle -- be able to generate ordered results more cheaply than one without
such an index, simply by walking that index first. You still need to tell it to do so.
Thanks,
-R
