- From: Henry Story <henry.story@bblfish.net>
- Date: Tue, 21 May 2013 20:40:01 +0200
- To: public-ldp-wg@w3.org
A few minor clarifications...
On 21 May 2013, at 20:00, Henry Story <henry.story@bblfish.net> wrote:
> (resending to get w3c into issue tracker)
> Let me take Nandana's first bug tracking example and show how one can do
> without membershipPredicate as set out by ISSUE-71.
>
> On 21 May 2013, at 18:30, Nandana Mihindukulasooriya <nmihindu@fi.upm.es> wrote
> in the email at http://lists.w3.org/Archives/Public/public-ldp-wg/2013May/0169.html
>
>> ----------------------- Model 1 --------------------------------------
>>
>> <http://example.org/app/BugTracker> a ldp:Container, bt:BugTracker ;
>> ldp:membershipPredicate bt:tracksProduct ;
>> bt:tracksProduct <http://example.org/app/BugTracker/ProductA> .
>> ------
>> <http://example.org/app/BugTracker/ProductA> a ldp:Container, bt:Product;
>> ldp:membershipPredicate bt:hasBug ;
>> bt:hasBug <http://example.org/app/BugTracker/ProductA/Bug1> .
>> ------
>> <http://example.org/app/BugTracker/ProductA/Bug1> a bt:Bug;
>> dcterms:title "Product A crashes when shutting down.";
>> dcterms:creator <http://example.org/users/johndoe>;
>> dcterms:created "2013-05-05T10:00"^^xsd:dateTime
>> bt:isInState "New" .
>
> So a few remarks on this modelling, which I think is worth opening a new issue
> for by itself on. Your model is confusing a thing - a bug - and an information resource
> that describes it.
> This means that it is not going to be possible later to identify two bugs with owl:sameAs
> without coming to the conclusion that it was created at different times, by potentially two
> people. It also means you cannot distinguish copyrights on the information content -
> a creative commons licence - from the bug itself, which is not something that can be
> licenced.
> So this is a first reason why this type of modelling is not standard, and not a good
> idea. And another reason why the ldp:membershipPredicate is going to walks straight
> into the -1 of a lot of people at the w3c if it is kept like that.
>
> So let me here try to bypass this problem and see how far I can go.
> Let us say </bugs/> is our container with the following content:
>
> ~~~~~~~~~~
> <> a ldp:Container, bt:BugReport;
This should be named something like bt:BugReportContainer rather that bt:BugReport.
One could perhams even use owl Restrictions to define a class like that.
> val:primaryTopicRestriction [ onProperty bt:product
> hasValue <http://example.org/app/BugTracker/ProductA> ];
So again this is a restriction of the primaryTopic of the members of the container.
another name could be val:memberPrimaryTopicRestriction .
> bt:member <bug1>, <bug2>, <bug3> .
>
> # note that we add metadata on the information resource
> # note also that the creator is the creator of the bug report, not the creator of the bug
>
> <bug1> dcterms:title "Product A crashes crashes when starting up.";
> dcterms:creator <http://example.org/jack#me>;
> dcterms:created "2013-04-05T10:00"^^xsd:dateTime .
>
> <bug2> dcterms:title "Product A crashes when shutting down.";
> dcterms:creator <http://example.org/users/johndoe#i>;
> dcterms:created "2013-05-05T10:00"^^xsd:dateTime .
>
> <bug3> dcterms:title "My pictures looks funny when I click the red buton";
> dcterms:creator <http://facebook.com/users/grannySmith#>;
> dcterms:created "2013-05-06T11:23"^^xsd:dateTime .
> ~~~~~~~~~~~
>
> So we assume we have some validation description that will be
> arrived at by the rdf-validation group:
> https://www.w3.org/2012/12/rdf-val/Overview.php
> and that allows us to restrict the primary topics of posted content to
> be about ProductA .
>
> From this a client would know that all members of the container are
> bug reports, and that the bugs
... these bug reports describe ...
> must be about about a specific topic.
>
> We publish metadata about <bug1> and <bug2> which are bug REPORTS, not
> bugs. The Bug reports may themselves be buggy.
> These bug reports would then say something simple like
>
> <bug1> log:semantics {
>
> <bug1> dcterms:title "Product A crashes crashes when starting up.";
> dcterms:creator <http://example.org/jack#me>;
> dcterms:created "2013-04-05T10:00"^^xsd:dateTime ;
> foaf:primaryTopic <bug1#y> .
>
> <bug1#y> a bt:Bug;
> bt:product <http://example.org/app/BugTracker/ProductA> ;
> bt:isInState "closed";
> bt:cause <http://other.project.org/bugs/bug100#y> .
> }
( I of course mean that the bug reports contain what is inside the
parenthesis ie, after " <bug1> log:semantics { " )
>
> And now the bug report <bug2>
>
> <bug2> log:semantics {
>
> <bug2> dcterms:title "Product A crashes when shutting down.";
> dcterms:creator <http://example.org/users/johndoe#i>;
> dcterms:created "2013-05-05T10:00"^^xsd:dateTime ;
> foaf:primaryTopic <bug2#y> .
>
> <bug2#y> a bt:Bug;
> bt:product <http://example.org/app/BugTracker/ProductA> ;
> bt:isInState "open";
> owl:sameAs <bug3#y> .
> }
>
> Here an engineer determined that <bug2#y> was the same as <bug3#y> though
> he has two different bug reports
which clearly are not owl:sameAs each other
>
> So now we have a case where it is clear how
> 1. a client knows what to POST
by looking at the restrictions on what the members are.
> 2. the LDPC never uses anything else other than ldp:member
I meant he never uses anything other than rdf:member
> 3. we correctly make the distinction between information resource and thing talked about
(the bug report and the bug)
> 4. and we don't need membershipPredicate
which makes it easier to find the members since all members can be found simply
by searching
SELECT ?m WHERE { <> rdf:member ?m }
>
> It is true we need a vocabulary for restrictions on contents, but that we needed
> anyway and that is something that clearly can be done by a group such as the
> RDF-Validation group https://www.w3.org/2012/12/rdf-val/Overview.php
>
> Hope this helps,
>
> Henry
>
> Social Web Architect
> http://bblfish.net/
Received on Tuesday, 21 May 2013 18:40:36 UTC