RE: Innovation, community and queries


Both a human-writable and machine-processable syntax are desirable.  I hope
a separation so that the query language is defined by its computational
model, and has sveral syntaxes for different domains.  I'm not strongly for
or aginast an on SQL syntax - it is familiar to people - but it is necessary
to have a syntax that is convenient for script writers and application
programmer to write.  RDF is not that syntax.

As we are in the RDF realm, it would be good for the machine processable
form to be RDF like QEL or REGS :-).

Off to read your QL spec ...


-----Original Message-----
From: Patrick Stickler [] 
Sent: 23 May 2002 14:14
To: ext Seaborne, Andy; 'Jeen Broekstra'; Graham Klyne; Aaron Swartz
Cc: RDF Interest
Subject: Re: Innovation, community and queries

I would like to see a standardized RDF QL *in* RDF. It is hard to get folks
to learn "yet another language" and having a means to express
query-by-example in RDF makes it easier for users who already are familiar
with RDF/XML to use it.

I appreciate that SQL is a well established and widely known query language,
but I see no overwhelming reason why an RDF QL need emulate it.

Attached is an RDF schema and some additional explaination of such an RDF QL
in RDF that I've myself been working on. Comments very welcome.



On 2002-05-23 8:42, "ext Seaborne, Andy" <>

>> There are several good proposals for QLs out there, and I think that 
>> creating a "working draft QL" hybrid of a couple of these would be a 
>> seriously good idea.
> This is a good way forward - take the first generation languages and 
> consolidate the ideas.
> It would really help toolkit/framework builders, both current ones and 
> future ones to have one common QL.  It would help semantic web 
> application builders to have a common language they could get to 
> learn.  It would help tool builders to be independent of the RDF 
> system they would otherwise need to choose.
> Andy
> -----Original Message-----
> From: Jeen Broekstra []
> Sent: 23 May 2002 13:15
> To: Graham Klyne; Aaron Swartz
> Cc:
> Subject: Re: Innovation, community and queries
> Graham,
> On Thursday 23 May 2002 01:40, Graham Klyne wrote:
>> As someone who has recently designed and implemented a (yet
>> another) RDF query "language", I'm not convinced we're ready to 
>> standardize. I'm not convinced we know enough about the performance 
>> issues in RDF, and I'm also not convinced that standardizing a query 
>> language at this time would bring great benefits.  But I could be 
>> wrong on both counts.
> A possible benefit I see of standardizing on an RDF QL would be to 
> harness efforts made in several groups to optimize tools for "their 
> own" QL into a single framework. This makes it much easier for such 
> groups to compare results and benefit from each other.
> There are several good proposals for QLs out there, and I think that 
> creating a "working draft QL" hybrid of a couple of these would be a 
> seriously good idea. In fact, we have some plans of our own to try 
> this, but we haven't pursued this further sofar, because we do not 
> think it is a good idea to propose Yet Another RDF QL[tm] on our own.
> As for performance issues, I do not think that should be an impediment 
> to standardizing on a language, or at least making a "starting effort" 
> to do so. The implementation and storage format should be seen as 
> seperate from the QL spec, I think. I would say that expressive power 
> and complexity/"learning curve" are the most important parameters for 
> any QL.
>> My own intuition is that a query language for RDF should aim to 
>> operate at a higher level than "find this pattern of triples", but in 
>> my implementation it was hard to break away from.
> I am not quite sure what kind of higher level you have in mind. Do you 
> mean something like RDF Schema semantics interpretation, or something 
> more along the lines of query formulation in natural language?
>> I'd like to see more work on storage formats before we
>> nail down a query language.
> As I said, I think they are seperate issues. I'm hammering this 
> because the system I work on (Sesame) operates on the premise that 
> storage and retrieval are completely abstract operations. The query 
> interpreter does not have knowledge of the storage format, nor is the 
> storage format dependent on the QL we use.
> Regards,
> Jeen

Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email:

Received on Thursday, 23 May 2002 10:15:25 UTC