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Re: Property Path Profiles

From: Ivan Herman <ivan@w3.org>
Date: Tue, 12 Jan 2010 09:42:27 +0100
Message-ID: <4B4C35F3.4040306@w3.org>
To: matthew.perry@oracle.com
CC: W3C SPARQL Working Group <public-rdf-dawg@w3.org>


On 2010-1-11 20:12 , Matt Perry wrote:
> Hi Ivan,
> 
> Basically, combinations of complex paths are not supported.
> 
> For example, { :v1 :myProp1* :v2 }, { :v1 :myProp2+ :v2 }, and { :v1
> :myProp3? :v2 } are all supported, but { :v1
> :myProp1*/:myProp2+/:myProp3? :v2 } is not supported.
> 
> Hope this helps,

Yes, it does. Thanks.

My next question (and this is not to you exclusively!) is how do we
define the term 'profile' for SPARQL. Obviously, if this mechanism is
used for property paths, one can imagine coming it up for other
linguistic features that we may have. It is doable; I do not know how
much time and energy it would mean to define the term properly in general.

Ivan

> -Matt
> 
> Ivan Herman wrote:
>> Matt,
>>
>> to make things more understandable (for me:-) can you summarize what are
>> the features in the current property path document[1] that are _not_
>> covered? Ie, what do we give up if we use such profile(s)?
>>
>> Thanks for your help
>>
>> Ivan
>>
>> [1] http://www.w3.org/2009/sparql/docs/property-paths/Overview.xml
>>
>> On 2010-1-11 19:25 , Matt Perry wrote:
>>  
>>> Hi,
>>>
>>> During the last TC, I mentioned the possibility of a Property Paths
>>> profile that identifies a subset of property path queries that can be
>>> expressed with SQL. Such a profile would make it easy for triple stores
>>> implemented on top of relational databases to identify the set of
>>> property path queries that they "natively" support.  The purpose of this
>>> email is to start a discussion about the possibility of property path
>>> profiles.
>>>
>>> The grammars below show two possible fragments that we have identified.
>>> The first grammar is for SQL + CONNECT BY (Oracle) and the second is for
>>> PLAIN SQL.
>>>
>>> CONNECT BY:
>>>
>>> ALT  -> URI | URI|ALT
>>> SEQ  -> URI | URI/SEQ
>>> Elem -> URI | SEQ   | ALT   | ^URI
>>> COMP -> URI | Elem* | Elem+ | Elem{n,m} | Elem?
>>> TOP  -> URI | COMP  | ALT   | SEQ       | ^URI
>>>
>>> PLAIN SQL:
>>>
>>> ALT  -> URI | URI|ALT
>>> SEQ  -> URI | URI/SEQ
>>> Elem -> URI | SEQ       | ALT   | ^URI
>>> COMP -> URI | Elem{n,m} | Elem?
>>> TOP  -> URI | COMP      | ALT   | SEQ   | ^URI
>>>
>>> Thanks,
>>> Matt
>>>
>>>
>>>
>>>     
>>
>>   
> 
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
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Received on Tuesday, 12 January 2010 08:41:45 GMT

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