Re: SPARQL Query language for RDF

Malcolm Crowe wrote:
> 
> Hi,

Hi Malcolm,

> I have noticed some small errors in section 12:
> 12.2.1 in the algorithm, LeftJoin(G,A,true) should read LeftJoin(G,SA,true)

In the conversion from query string to algebra expression, OPTIONAL translates 
to LeftJoin so OPTIONAL.  When SA is OPTIONAL(A), that is the syntax word 
OPTIONAL and a term already converted because the algorithm works bottom-up,
then the outcome is LeftJoin (G,A,true), the A being taken from the OPTIONAL. 
  The document is correct.

> 12.5 the evaluation of Filter(P,F) should read
> eval(D(G),Filter(P,F)) = Filter(eval(D(G),p),F)

Yes - it seems to have lost the pattern - correected to:

eval(D(G), Filter(F, P)) = Filter(F, eval(D(G), P))

The pattern and filter were the wrong way round as well.

Thank you for your comments,

	Andy


> Best wishes
> Malcolm
>  
> 
> Legal disclaimer
> 
> --------------------------
> 
> The information transmitted is the property of the University of Paisley 
> and is intended only for the person or entity
> to which it is addressed and may contain confidential and/or privileged 
> material. Statements and opinions expressed in this e-mail may not 
> represent those of the company. Any review, retransmission, 
> dissemination and other use of, or taking of any action in reliance 
> upon, this information by persons or entities other than the intended 
> recipient is prohibited. If you received this in error, please contact 
> the sender immediately and delete the material from any computer.
> 
> --------------------------
> 

-- 
Hewlett-Packard Limited
Registered Office: Cain Road, Bracknell, Berks RG12 1HN
Registered No: 690597 England

Received on Monday, 6 August 2007 08:48:42 UTC