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Re: Update on ORDERing solutions

From: Steve Harris <S.W.Harris@ecs.soton.ac.uk>
Date: Mon, 21 Mar 2005 14:49:21 +0000
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-ID: <20050321144921.GA13020@login.ecs.soton.ac.uk>

On Mon, Mar 21, 2005 at 11:42:58 +0000, Andy Seaborne wrote:
> >>Confusion point: SPARQL does not have commas so I omitted them here too 
> >>but then
> >>
> >>
> >>is confusing (it means descending-in-?v, ascending-in-?w but is very easy 
> >>to miss read).
> >>
> >>Alternative syntax: break from SQL, XQuery and have
> >> DESC(?v) ?w
> >>or some other clear association of modifier with expression.
> >>
> >>I prefer the (non-SQL) DESC(?x), ASC(xsd:integer(?x)) style for clarity.
> >
> >
> >Without commas? So do I, I think. I'm not toally happy about the fact that
> >ASC and DESC appear to be functions, unless they have some defination in
> >that sense.
> ASC[] and DESC[] would be a different from functions.  How's that?

I'm not sure if thats better or not.
> ASC[?x]
> DESC[xsd:integer(?v)]
> It would be nice to have a joining trailing marker
> ?x\ASC
> xsd:integer(?v)\ASC
> but I I can't think of one. \ is not a good choice!

Truely. I cant think of a good one, but given the definition of what the
functions do below (which seems good) I cant think of a funcitonal
definition of ASC() and DESC() that fits with that either.

It could be a modifier to the ORDER, eg.

which is
in SQL speak

Looses SQL familiriarity points though.
> >What does it return? A positional decimal? comparison function style -1,
> >0, +1?
> It returns an RDF value like any other function.  This isn't the collation 
> function, it is a transformation of the data.  cf. xsd:integer(?v) or 
> xsd:dateTime(?myDateFormat)

Hence the need for global ordering (int come before dates, etc.). Makes

- Steve
Received on Monday, 21 March 2005 15:05:11 UTC

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