[oslc-core] Resource shapes in query capability

[Arthur Ryman]

Joe,

The query base is itself a resource so the link to the resource shape 
describes the properties of the query base. You could GET the query base 
and receive back a resource with those properties (maybe a title or 
description, and lots of members). 

At least one of those properties should be a membership property, and the 
values (objects) of this member property are the resources that belong to 
the query capability. 

Below is a SPARQL graph pattern that I hope helps.

There are a few resources involved here, but they are all linked to each 
other. You start from the oslc:QueryCapability (?queryCapability) resource 
and get its oslc:ResourceShape (?queryBaseShape). You look at its 
oslc:Property resources and find the one that describes membership 
(?memberProperty). Then you look at its value to get the 
oslc:ResourceShape of the member resources (?memberShape).

 # this triple comes from the oslc:QueryCapability resource

?queryCapability oslc:resourceShape ?queryBaseShape .

 # these triples come from the oslc:ResourceShape resource of the query 
base

?queryBaseShape a oslc:ResourceShape .

?queryBaseShape oslc:property ?memberProperty .

# these triples come from the oslc:Property resource for the member 
property of the query base

?memberProperty a oslc:Property .

?memberProperty oslc:isMemberProperty true .

?memberProperty oslc:valueShape ?memberShape .

# ?memberShape is the oslc:ResourceShape of the member resources
 
Regards, 
___________________________________________________________________________ 

Arthur Ryman 

DE, PPM & Reporting Chief Architect
IBM Software, Rational 
Toronto Lab | +1-905-413-3077 (office) | +1-416-939-5063 (mobile) 





From:
Joe Ross <joeross at us.ibm.com>
To:
oslc-core at open-services.net
Cc:
Denilson Nastacio <dnastaci at us.ibm.com>
Date:
09/18/2011 07:14 PM
Subject:
[oslc-core] Resource shapes in query capability
Sent by:
oslc-core-bounces at open-services.net




We are trying to use resource shapes to advertise metadata about resources 
types that can be queried by OSLC clients. However, the description in the 
table in the OSLC Core spec seems to indicate a different usage, which is 
not clear: 

"oslc:resourceShape  zero-or-one  ... The Query Capability SHOULD provide 
a Resource Shape that describes the query base URI. " 

Is the intent that a query capability can only be used to query for 
instances of a single type of resource, since "occurs" is zero-or-one? 
Also, not clear what is meant by "a Resource Shape that describes the 
query base URI." 

We thought that the Resource Shape would be used to describe the resources 
that are managed by the provider and can be searched/retrieved using the 
query URL. If not, then it's not clear where we can expose that metadata 
to clients. 

This other paragraph later on in the specification seems to describe the 
use that we intended: 

"An OSLC Service may provide one or more Query Capabilities to enable 
query of resources. A Query Capability provides a base URI for forming 
Query Resource URIs and MAY provide Resource Shapes that describe the 
property values that may be expected in the resources that are queryable 
via the query capability. Thus, Query Capabilities provide a way to 
discover the resources managed by an OSLC Service. " 

This seems to indicate that there can be multiple resource shapes for a 
query capability and that they describe properties of the resources being 
managed by the provider. 

Which of these is correct? 

Thanks, 

================================================
Joe Ross/Austin/IBM, joeross at us.ibm.com
Tivoli Autonomic Computing & Component Technologies
512-286-8311, T/L 363-8311_______________________________________________
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