[oslc-core] Resources from a different service

[Arthur Ryman]

Dragos,

If the linked resource is managed by the service then it should have a 
ResourceShape linked from the ServiceProvider resource. That should define 
the scope of resources you get in a query.

The approach at OSLC is to be flexible in order to reduce the development 
burden for service implementers. This creates a challenge for service 
consumers such as tools. Therefore, tools need to degrade function 
gracefully, i.e. handle cases where just a link is returned instead of all 
the requested inlined data values.


Regards, 
___________________________________________________________________________ 

Arthur Ryman, PhD, DE

Chief Architect, Project and Portfolio Management
IBM Software, Rational
Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063





From:
Dragos Cojocari <dragos.cojocari at ro.ibm.com>
To:
Arthur Ryman/Toronto/IBM at IBMCA
Cc:
oslc-core at open-services.net, oslc-core-bounces at open-services.net
Date:
10/21/2010 11:05 AM
Subject:
Re: [oslc-core] Resources from a different service



Hey Arthur, 

thanks for the feedback. The following statement is the core of my 
problem: 

>>  If you use the Simple  Query syntax, you'll receive as much data as 
the service can provide, but 
>> that may not include all the data you requested, i.e. you may have to 
>> explicitly GET resources that are linked. 
So the only way for a consumer to distinguish between non-existent linked 
resource and a linked resource that could not be inlined by the query is 
by looking at the response. Basically an entry like <usesTestCase 
rdf:resource="someURL"/> means that the resource needs to be individually 
retrieved but there is no way to determine this when looking at the 
Resource Shapes and building the queries? 

Regards, 
        Dragos 



Arthur Ryman <ryman at ca.ibm.com> 
21/10/2010 16:00 


To
Dragos Cojocari/Romania/IBM at IBMRO 
cc
oslc-core at open-services.net, oslc-core-bounces at open-services.net 
Subject
Re: [oslc-core] Resources from a different service








Dragos,

The ResourceShape resources describe the data model of the resources, not 
the contents of a data source. All you can assume is that if you GET a 
resource you'll receive an representation of it, If you use the Simple 
Query syntax, you'll receive as much data as the service can provide, but 
that may not include all the data you requested, i.e. you may have to 
explicitly GET resources that are linked.

We don't have a way to specify the precise contents of the data source. A 
resource may link to other resources in the same service or those in 
remote services.

This situation improves when the data from multiple sources is aggregated 
in a triple store and your can use SPARQL to query it.

Regards, 
___________________________________________________________________________ 


Arthur Ryman, PhD, DE

Chief Architect, Project and Portfolio Management
IBM Software, Rational
Markham, ON, Canada | Office: 905-413-3077, Cell: 416-939-5063





From:
Dragos Cojocari <dragos.cojocari at ro.ibm.com>
To:
oslc-core at open-services.net
Date:
10/21/2010 06:25 AM
Subject:
[oslc-core] Resources from a different service
Sent by:
oslc-core-bounces at open-services.net



Hey all, 

as resources exposed by one provider can be linked to resources from 
another provider some questions arise on how they can be retrieved: 
1. can the Resource Shape for a resource refer the resource shapes of the 
resources of the other domains in the oslc:valueShape property? 
2. if the answer to (1) is yes, and there is no obvious reason why it 
shouldn't be, can one query service aggregate resources from multiple 
providers? 

I believe the answer to (2) is NO and in this case a different question 
arises: how can a query consumer determine what resources can be obtained 
( aggregated/in-lined) from one query service? in other words, how can the 

consumer determine how to build the queries to retrieve the data: 
       - referenced resources from the same domain could be obtained with 
a single query crafted to in-line the properties of the referenced 
resources 
       - referenced resources from other providers would have to be 
requested using multiple queries sent to multiple query services. 

Example: 
- single provider: the details of a "QM V2 TestPlan" and its "QM V2 
TestCases" linked by http://open-services.net/ns/qm#usesTestCase ( as 
described by 
http://open-services.net/bin/view/Main/QmSpecificationV2Shapes) 
- multiple provider: the details of a "CM V2 Change Request" and the 
details of the "QM V2 Test Case" linked through 
http://open-services.net/ns/cm#testedByTestCase ( as described by 
http://open-services.net/bin/view/Main/CmSpecificationV2Shapes ) 

In the above examples the consumer needs to know that the details for the 
"QM V2 Test Case" cannot be obtained from the same query service as the 
"CM V2 Change Request". 

Thanks and regards, 
       Dragos 


Exceptand situatiile in care partile au convenit in alt mod: / Unless 
stated otherwise above:
IBM România S.R.L.
Bucharest Business Park, Corp A2, Şos. Bucureşti-Ploieşti Nr. 1A, 013681
Bucureşti 1, ROMANIA
CIF RO378660, RC J/40/5106/1991
Cap.Soc. 41.670 Lei_______________________________________________
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Exceptand situatiile in care partile au convenit in alt mod: / Unless 
stated otherwise above:
IBM România S.R.L.
Bucharest Business Park, Corp A2, Şos. Bucureşti-Ploieşti Nr. 1A, 013681
Bucureşti 1, ROMANIA
CIF RO378660, RC J/40/5106/1991
Cap.Soc. 41.670 Lei