Re: ISSUE-3

On Thu, Nov 12, 2009 at 5:23 PM, Richard Cyganiak <richard.cyganiak@deri.org
> wrote:

> On 12 Nov 2009, at 16:26, Ezzat, Ahmed wrote:
>
>> Given that the goal of the WG is to create a mapping from RDB Schemas to
>> RDF/OWL classes only.  This require us to be able to read the schema but not
>> necessarily to modify it.
>>
>
> +1 for scoping this WG to read-only access.
>
> +1 too!  In particular I think that stating "set of SQL DDL" is very
important.

We can then use the mapping language, to do the SPARQL2SQL. I know that this
is out the scope of the WG, but we have been able to show that commercial
sql optimizers can do the sparql2sql rewriting given the original RDB to OWL
classes. This is in our Ultrawrap system, that we will be presenting in two
weeks. You can see the poster about this that we presented at ISWC2009 here:

http://www.cs.utexas.edu/users/miranker/studentWeb/Ultrawrap_ISWC2009_Poster.pdf

>
>  This leads me: R2RML mapping language MUST support as complete as possible
>> all SQL data and object types and any exceptions will be identified as soon
>> as possible after the WG launch.
>>
>
> +1 for supporting as many SQL data types as possible. But what's the target
> for "all" data types? Does this include, say, the XML type of SQL:2003? What
> about types that are not in the standard but commonly used in popular RDBMS?
> I don't even know if SQL:2008 adds any new datatypes...
>
>
+1 for supporting as many SQL data types as possible too!

>
> Best,
> Richard
>
>
>
>
>> All, does the above capture what the goal is.
>> Feel free to edit/agree/disagree, etc..
>> Regards,
>>
>> Ahmed
>>
>>
>> -----Original Message-----
>> From: ashok malhotra [mailto:ashok.malhotra@oracle.com]
>> Sent: Thursday, November 12, 2009 05:34
>> To: Ezzat, Ahmed
>> Cc: RDB2RDF WG
>> Subject: Re: ISSUE-3
>>
>> Hello Ahmed:
>> I envision that the work of the WG is one-way: from RDB to RDF/OWL.
>> So, to answer your question, I do not envision creating SQL tables in
>> the RDBMS from SPARQL application using R2RML.
>> All the best, Ashok
>>
>>
>> Ezzat, Ahmed wrote:
>>
>>> Hi Ashok,
>>>
>>> Thanks for the follow up. I agree with your clarification regarding the
>>> mapping SPARQL to SQL is out of scope; having discussion about it if the
>>> team want to pursue is fine - I am trying to separate what we discuss, with
>>> time constraints, from what we will commit to deliver which we need to pin
>>> down early 2010.
>>>
>>> I liked the D2R presentation scope in the mapping area; is reasonable.
>>>
>>> Regarding DDL statements mapping support: do you envision creating SQL
>>> tables in the RDBMS from SPARQL application using R2RML or do you envision
>>> the ability through the R2RML to read the different schema objects
>>> definitions in the RDBMS from a SPARQL application?  I agree that the latter
>>> is a must and would be interested in getting your input as well as others on
>>> the first.
>>> Regards,
>>>
>>> Ahmed
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: public-rdb2rdf-wg-request@w3.org [mailto:
>>> public-rdb2rdf-wg-request@w3.org] On Behalf Of ashok malhotra
>>> Sent: Wednesday, November 11, 2009 13:58
>>> To: RDB2RDF WG
>>> Subject: ISSUE-3
>>>
>>> Since the goal of the WG is to create a mapping from RDB Schemas to
>>> RDF/OWL classes, perhaps
>>> we should rephrase the bullet point in the requirements as
>>>
>>>   * The mapping language MUST define the set of SQL DDL
>>>     to be supported in the first release. The set to be supported
>>>     SHOULD be as complete as possible and be defined as soon as
>>>     possible after the WG official launch.
>>>
>>> This will let us exclude Table Types if we wish.
>>>
>>> I apologize that the original bullet was interpreted to mean that the
>>> the WG should define
>>> a mapping from SPARQL to SQL.  That was not the intention.  In my view,
>>> the mapping of
>>> SPARQL to SQL should be left open as a technology on which various
>>> implementations
>>> can compete. .
>>>
>>>
>>
>
>