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Re: [DTB] Most editor's notes addressed

From: Axel Polleres <axel.polleres@deri.org>
Date: Mon, 24 Nov 2008 15:46:23 +0000
Message-ID: <492ACC4F.5040105@deri.org>
To: Chris Welty <cawelty@gmail.com>
CC: Jos de Bruijn <debruijn@inf.unibz.it>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Chris Welty wrote:
> 
> Axel Polleres wrote:
>>>> I was hoping we could get BLD a usable rules language for RDF,
>>>> compatible with SPARQL. (And similar problems will arise if we 
>>>> pursue to
>>>> suggest RIF to the RDB2RDF people: If we as a working group approach
>>>> them and say: look at RIF, we should then not be in the position that,
>>>> if they agree to do so, having to answer them: "BUT, BTW RIF doesn't
>>>> work for that, you need to do your own dialect from scratch, your
>>>> problem...")
>>>>
>>>> I see some very fundamental issues here.
>>>
>>> I would be very interested to see whether there are any features
>>> required by RDB2RDF that are not provided by RIF.
>>
>> I have no concrete example as of now, but my rationale is: if we run 
>> into troubles with SPARQL, we might also run into troubles with SQL, 
>> since they share many underlying assumptions.
> 
> If you're going to judge BLD by itself in terms of its suitability to 
> address the requirements of datatabase query language you will certainly 
> find it falls short.  So don't set unreasonable expectations - BLD is 
> the *basic* *logic* dialect.  I realize you know this, but when you say 
> "I was hoping we could get BLD a usable rules language for RDF, 
> compatible with SPARQL," it makes me think you've forgotten.
> 
> The RIF approach to something like RDB2RDF would be to start with BLD 
> and then extend it to a dialect that supports the additional things they 
> need. And depending on how hard you stress "need" (as opposed to "want" 
> or "would find convenient") you will probably find the dialect is not a 
> big extension.

I agree.

BTW: An example of what they explicitly mentioned and which is not 
covered per se in RIF are aggregates.

> [As an aside, I was just working with some DB folks last week here (on 
> something unrelated) and overheard the comment, "most experts know the 
> 2/3 of SQL to avoid".  SPARQL also has its things to avoid.]
> 
> -Chris
> 


-- 
Dr. Axel Polleres
Digital Enterprise Research Institute, National University of Ireland, 
Galway
email: axel.polleres@deri.org  url: http://www.polleres.net/
Received on Monday, 24 November 2008 15:47:08 GMT

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