[Nepomuk] Re: Special Identifying Properties

[Vishesh Handa]

On Thu, Jul 28, 2011 at 12:46 AM, Sebastian Trüg <trueg at kde.org> wrote:

> How about another parameter instead which specifies these kind of
> properties in a list. Then a client can define what makes sense.
>

That would increase the complexity of storeResources from a clients point of
view. But I suppose we should provide overloaded variants of storeResources.

The reason I want to specify this in the ontology is that I can't think of a
single use case where any of these properties would not be globally
identifying. Here is an idea : Maybe we could mark these properties as
InverseFunctionProperties ( inverse cardinality = 1 ), that way we know for
a fact that they are globally identifying.


>
> Just an idea...
>
> Cheers,
> Sebastian
>
> On 07/27/2011 04:53 PM, Vishesh Handa wrote:
> >
> >
> > On Wed, Jul 27, 2011 at 8:13 PM, Sebastian Trüg <trueg at kde.org
> > <mailto:trueg at kde.org>> wrote:
> >
> >     could you please elaborate on the need of a primary key type of
> >     property. Give an example maybe...
> >
> >
> > Of course
> >
> > Imagine I already have a contact in my repo -
> >
> > <nepomuk:/res/somecontact>
> >     a nco:PersonContact ;
> >     nco:fullName "Some name" ;
> >     nco:hasEmailAddress <someEmailRes> .
> >
> > Now I decide to push some data using storeResources
> >
> > SimpleResource res;
> > res.addType( NCO::PersonContact() );
> > res.addProperty( NCO::hasEmailAddress(), QUrl("someEmailRes") );
> > res.addProperty( NCO::fullName(), QLatin1String("Some other name") );
> >
> > This contact would normally not get identified as
> > <nepomuk:/res/somecontact> as it has a different first name. However,
> > two people can never have the same email address, so in this case it
> > *should* get identified as <nepomuk:/res/somecontact>. ( Merging would
> > obviously fail, but that is another issue, we could be using
> > OverwriteProperties )
> >
> > If we marked nco:hasEmailAddress as Globally Unique, then the SimpleRes
> > would get mapped to <nepomuk:/res/somecontact> as the email matches.
> >
> > Same is the case for nfo:hashValue
> >
> >
> >
> >     On 07/27/2011 04:26 PM, Vishesh Handa wrote:
> >     > Hey Everyone
> >     >
> >     > Martin and I were discussing storeResources yesterday, and we
> stumbled
> >     > on the need to have certain properties act as Primary Keys for
> >     > Resources. Currently, storeResources treats the nie:url as a
> Primary
> >     > Key, only if the nie:url is not present does it use the literal
> >     > identification scheme ( read datamanagement.h for more info )
> >     >
> >     > With Martin working on pimo:Person and nco:PersonContact
> >     aggregation, he
> >     > requires the nco:hasEmailAddress to act as a Primary Key.
> >     Additionally I
> >     > would like nfo:hashValue to act as one. So now that we have 3
> >     > contenders, it makes sense to mark these properties in the
> >     ontologies as
> >     > globally identifying or something.
> >     >
> >     > What do you guys think? If you approve, can you suggest a way to
> mark
> >     > these properties?
> >     >
> >     > One option is that we have a nxx:globalIdentifyingProperty, and
> make
> >     > nie:url, nco:hasEmailAddress, and nfo:hashValue subclasses of it.
> >     >
> >     > --
> >     > Vishesh Handa
> >
> >
> >
> >
> > --
> > Vishesh Handa
>



-- 
Vishesh Handa
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