RE: Start discussion

Hi Juan,

We have tasks for the use case.  I agree that I do not see enough discussion on the distribution list. It was agreed on we need the use case completed before diving deeper in the mapping language. This Tuesday let us discuss what is left on the use case. Our highest priority is to finalize what the team will be delivering sometime in April - higher priority than the semantics of the language.

I agree for using Datalog in expressing the semantics of the mapping language; we should discuss that in the group. If I remember correctly, Andy Seaborne used Datalog in expressing the semantics of some SPARQL language constructs in the SPARQL WG...

Lee, Independent of which approach you use, you need to validate the semantics of the mew language.  Advantage of Datalog, as it is based on logic, it is more expressive than relational algebra. Below is few pages about Datalog.


Regards,

Ahmed



-----Original Message-----
From: public-rdb2rdf-wg-request@w3.org [mailto:public-rdb2rdf-wg-request@w3.org] On Behalf Of Lee Feigenbaum
Sent: Sunday, March 21, 2010 5:51 PM
To: Juan Sequeda
Cc: public-rdb2rdf-wg@w3.org
Subject: Re: Start discussion

On 3/21/2010 8:26 PM, Juan Sequeda wrote:
> Hi Everybody,
>
> There has been no discussion at all on the list, and that honestly
> worries me.

I share this concern, which is one reason that I decided to join the
group and try to add what I can.

> I know that we need to have a Use Case documents, but it is not
> completely clear to me what else we need to turn in and by when.
>
> One issue that I personally feel than needs to be settled is the
> semantics of the language. One we have this defined, it is just a matter
> of deciding on what is the syntax. I don't think we have made much
> progress on this issue. I have proposed to develop the semantics of the
> mapping language in datalog. I'd be up for working on this in
> conjunction with Marcelo Arenas and Dan Miranker.

Ideally, I'd hope that the semantics of the language follow from the
requirements which follow from the use cases.

As far as datalog, I know next to nothing about it, so my questions are
probably naive. Is there a datalog standard that we will be able to
normatively reference if the semantics of the language are given in
datalog?

Also, I'm not sure if separating the syntax & semantics is definitely an
easy thing to do. I know that there are people on the group who advocate
that the mapping language be based on SPARQL CONSTRUCT queries combined
with a default mapping from the relational model to the RDF model. In
this case, I imagine it would make more sense to lean on the SPARQL
algebra/semantics?

Lee

> What else should we be having discussions on? The clock is ticking.
>
>
> Juan Sequeda
> +1-575-SEQ-UEDA
> www.juansequeda.com <http://www.juansequeda.com>