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Re: R2RML practicability concerns

From: Souripriya Das <souripriya.das@oracle.com>
Date: Wed, 06 Oct 2010 01:12:53 -0400
Message-ID: <4CAC0555.7040707@oracle.com>
To: Sören Auer <soeren.auer@gmail.com>
CC: RDB2RDF WG <public-rdb2rdf-wg@w3.org>
I believe that the R2RML mapping language must allow full mapping 
functionality. However, to address the other extreme of the spectrum and 
points in between, R2RML should provide shortcut constructs where 
default/automatic mappings can be specified with very concise mapping 
specification. (Please note, however, that the example we have included 
in the current draft is probably artificially complex because its main 
purpose was to illustrate most if not all functionality allowed by R2RML.)

We will add constructs that will allow minimal mapping specification 
that can be used and also that can be incrementally refined, if necessary.

- Souri.

On 10/5/2010 7:15 PM, Sören Auer wrote:
> Dear all,
> unfortunately there was not time today during the telco to raise this 
> concern, that is why now by email:
> When looking at the example I notice, that the relational tables 
> definition would be very concise (~15 lines). The R2RML mapping, 
> however, is very verbose and takes probably 5 times more space.
> I'm really afraid, that R2RML will be very impractical and has a quite 
> steep learning curve. Even if you have user interfaces which 
> automatize the generation of R2RML, these will have to be understood 
> and modified manually as soon as the DB schema changes. From that 
> perspective, the current draft appears to be quite impractical.
> Suggestion: do you think it would be possible to follow a convention 
> over configuration approach and only require the user to configure 
> something in case he wants to alter the default behaviour. For 
> example, an rr:Table2TriplesMap based on an rr:logicalTable could be 
> mapped based on reasonable assumptions and maybe a default mapping of 
> DB datatypes to XML-Schema datatypes, instead of having to configure 
> every rr:propertyObjectMaps in addition for every column.
> I think simplifying things is really crucial, if we want the standard 
> to be quickly and widely adopted.
> Best,
> Sören
Received on Wednesday, 6 October 2010 05:14:47 UTC

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