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Re: sparql language editorial comments section 2.1-2.5

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 13 Jun 2005 14:37:29 +0100
Message-ID: <42AD8C19.8010206@hp.com>
To: Jeen Broekstra <jeen@aduna.biz>
CC: RDF Data Access Working Group <public-rdf-dawg@w3.org>

Jeen Broekstra wrote:
> editorial comments on SPARQL language editor's draft rev 1.379
> http://www.w3.org/2001/sw/DataAccess/rq23/
> =======
> Section 2.1 first paragraph: "The SELECT clause identifies...". The
> SELECT in this sentence should be in a different font.


> In the subsection "Query Term Syntax" the notions of PREFIX and BASE 
> are introduced. The difference between the two is not sufficiently 
> explained. (I would suggest an improvement but to be honest I'm not 
> sure I understand the difference myself).

Base IRIs are for things like <.>, <#>, <a> or <#foo> - relative IRI references 
that need turningg into absolute form (begin with a scheme name, worry about . 
and .. etc )

> In the subsection "Examples of Query Syntax" an example is given of
> three ways to express the same query. The example is not correct: in
> the first two queries 'book1' resolves to the full URI
> <http://example.org/book/book1>, while in the third (and fourth) it 
> resolves to <http://example.org/book/shelf/book1>. Suggestion: to fix, 
> change the BASE definition in the third and fourth query to 
> <http://example.org/book/> (so without 'shelf' in the path).


> In the subsection "Data  description used in the document" first sentence:
>   "The data format used in this document is Turtle used to show each
>    triple explicitly."
> I think this is grammatically incorrect, at least it's unclear what is 
> meant exactly. Suggestion to clarify by rewording to:
>   "The data format used in this document is Turtle, since this format
>    allows showing each triple explcitly." or alternatively "....since
>    this format is [relatively] well suited for human readability."

The point is that it is one style of Turtle always having all three parts of the 
triple explicit (no ";").

> An example Turtle document is presented in this section, using
> Turtle's prefix mechanism. Suggestion: point out explicitly in the
> text that Turtle uses an '@' in front of the prefix def, but SPARQL
> does not.

I'd prefer to reference Turtle, not explain it.  I am worried that adding 
material about Turtle will confuse the matter of what is SPARQL, rather than help.

> Section 2.3 is titled "Basic Graph Patterns". However, the section is
> actually about triple patterns. Rename to "Triple Patterns".


> Section 2.4 is titled "Matching Basic Graph Patterns". Suggest to
> rename to "Basic Graph Patterns and Solutions".

This would be at odds with other sections which just mention the pattern form.

> The definition of 'Basic Graph Pattern' refers to triple patterns.
> Suggestion to link to the definition of triple pattern.

> Section 2.5 "Examples of Basic Graph patterns"
> First sentence:
>   "The SPARQL syntax uses the keyword WHERE to introduce the Query
>    Pattern".
> Suggestion: link to definition of Query Pattern.

There is no longer a formal definition of query pattern.

> Despite the title the section only contains one example of a basic
> graph pattern. 


> The text immediately launches into an explanation of
> blank nodes which confuses the issue, since that is not what the
> section is supposed to be about. Suggestion: use a simpler example and
> focus exclusively on the issue at hand, namely graph patterns. Replace
> explanation of the role of blank nodes with a pointer to section 2.7.

Done the latter (down play blank nodes) but left the example as-is for now.

> Further suggestion: include more than one example.


> Jeen

Received on Monday, 13 June 2005 13:39:24 UTC

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