Re: Strawman for a custom R2RML syntax

Hello Richard,


>The strawman is here:
> 
> http://www.w3.org/2001/sw/rdb2rdf/wiki/R2RML_in_a_custom_syntax
> 
> It's indeed quite concise, which is nice.
> 
> 

Wow. I like it. That's quite close to my own draft where current
Virtuoso RDF Views come from. That's probably the best variant that can
be designed without gathering real use cases and hitting real
compilation problems, i.e., designed without writing a complete
implementation.

Now let's extend the draft with options.

Let us assign an (optional) name for every triple pattern of these
templates, for diagnostic purposes.
Let's cut the SQL select in parts and combine them automatically,
otherwise it is impossible to compose an adequate SQL join for a given
basic graph pattern.
Let us enrich IRITEMPLATEs by adding options absolutely needed for the
optimizer (and by making them based on functions when needed). Let's
specify the order of patterns and let some "exceptions" take priority on
"common cases", to cut useless unions.
Let's manipulate them (add/remove/reorder) and let's do that in parts,
because many independent applications may share one RDF storage and they
can be removed as well as installed.

These four extensions will give us an absolute minimum needed for a real
life installation. Unfortunately, as a bad side effect, they will bloat
the example to the complexity of Virtuoso's RDF Views.

We can also start from other end --- given the current syntax of RDF
Views, try to remove features to make it simple. Unfortunately, for
every given feature there will be a sample data mapping and a query that
will go slower at least order of magnitude without the excluded feature.

That's why I'm staying silent in this group. I simply don't know how to
make the thing both simple and usable. I know only what's absolutely
needed for some common tasks but is still missing in these RDF Views
because I will not be able to maintain the additional code.

Best Regards,

Ivan Mikhailov
OpenLink Software
http://virtuoso.openlinksw.com

P.S. I forgot to mention two more extensions, for free text and  for
LITERALTEMPLATES :(

Received on Monday, 30 August 2010 09:10:20 UTC