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RE: Re: why arcs never be merged?

From: Danny Ayers <danny666@virgilio.it>
Date: Fri, 29 Nov 2002 16:13:52 +0100
To: <jeffzhang726@yahoo.com.cn>, "Graham Klyne" <GK@ninebynine.org>
Cc: <www-rdf-interest@w3.org>
Message-ID: <EBEPLGMHCDOJJJPCFHEFGEJGIKAA.danny666@virgilio.it>


>Dear Graham,
> I mean the first example
>    ex:foo ex:property ex:bar .
>and
>    ex:foo ex:property ex:bar .
>    ex:foo ex:property ex:bar .
>
>Our team is developping an rdf engine which has an API as its part.
>When we discuss about the operation of adding a statement to a
>graph, we are puzzled
>about whether a statement should be added to the graph if there is
>already a same
>statement in the graph. As to the rule of merging graphs, it seems
>the same statement should be added to the graph. But we can not
>find any real world example in which multiple copies of statements
>make different meanings with single statement. Is there any example?

(not Graham, but still)

let me try...I hope I've got this right...

if we assert a couple of statements

http://example/x dc:creator Jeff
http://example/x dc:creator Jeff

then ask the question,

http://example/x dc:creator ?

then we should get the answer

http://example/x dc:creator Jeff

or

http://example/x dc:creator Jeff
http://example/x dc:creator Jeff

or even

http://example/x dc:creator Jeff
http://example/x dc:creator Jeff
http://example/x dc:creator Jeff

- they're all true

if had asserted instead

http://example/x dc:creator Jeff
http://example/x dc:creator Ora

the answer could have been

http://example/x dc:creator Jeff
http://example/x dc:creator Ora

or

http://example/x dc:creator Ora
http://example/x dc:creator Jeff
http://example/x dc:creator Jeff

or other variations, depending on the app. In practice I suppose we'd avoid
having the query just return a 'null' statement, even though that would in
effect be true too. So in an app I would be tempted to go for the simplest
solution, i.e. merge two identical statements into one.

Cheers,
Danny.
Received on Friday, 29 November 2002 10:25:41 GMT

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