[oslc-core] Resources from a different service

[Arthur Ryman]

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 


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