Re: Future-Proofing for Transition to Multi-Edge caused by Data Arrival

On 26/01/2023 17:21, Pierre-Antoine Champin wrote:
>
>
> On 26/01/2023 16:55, Gregory Williams wrote:
>>> On Jan 26, 2023, at 6:06 AM, Souripriya Das 
>>> <souripriya.das@oracle.com> wrote:
>>>
>>> Initial Data (no shortcuts, to avoid hiding important details):
>>> ------------------------------------------------------------------------------
>>>     :Bush :servedAs :President .
>>>     << :Bush :servedAs :President >> :index 43 .
>>>     :Obama :servedAs :President .
>>> << :Obama :servedAs :President >> :index 44 .
>>>     :Trump :servedAs :President .
>>>     << :Trump :servedAs :President >> :index 45 .
>>>     :Biden :servedAs :President .
>>> << :Biden :servedAs :President >> :index 46 .
>>
>> …
>>
>>> Let's say that in 2024 Trump wins again. How will the data get 
>>> represented in RDF-star? Since RDF-star, like RDF, has "no duplicate 
>>> triples" constraint, the data creator has to extend the schema to 
>>> introduce a new structure that involves a new property, 
>>> :occurrenceOf. Since the above query was written without expecting 
>>> the new structure, it has to be modified as well.
>>
>>
>> Souri –
>>
>> I’m not sure I understand the issue here. Won’t the original query 
>> work just fine if the input data contains an extra index value?
>>
>> << :Trump :servedAs :President >> :index 45, 47 .
>>
>> =>
>>
>> :Bush
>> :Obama
>> :Trump
>> :Biden
>> :Trump
> It does work indeed in this simple example, but it would break if you 
> added multiple attributes for each presidential term: index, 
> start-date, end-date, vice-president...

But that's actually a good point, because

* There are situations where the "unique triples" stance of RDF-star 
does /not/ cause any problem (namely, when the edges have a single 
property).

* If you now want to add a second property, say start-date, then 
RDF-star requires a re-modelling (using the "occurrenceOf" pattern), 
while with Property Graphs, there would be no change in your model (just 
stick another property in your edges)

* If you now want to add a third property, say vice-predident, then your 
have no problem in RDF-star, just add the property to the object node of 
your "occurrenceOf" predicate. In Propery Graphs, on the other hand, you 
need to change your edges into nodes, because PGs can not relate edges 
to nodes...

Repeating my previous point 
<https://lists.w3.org/Archives/Public/public-rdf-star-wg/2023Jan/0035.html>: 
in all languages, some evolutions are smooth, some evolutions are more 
disruptive. The solution, IMO, is not to push the tipping point further 
down the road, but to encourage robust modelling in the first place.


>>
>> Thanks,
>> Greg
>>