RE: Glossary for the working group

A constraint specifies what graph patterns it will check. 

For example, it may check to ensure that for any resource the value of example:startDate is less than the value of example:endDate.

If this constraint is attached to a specific class, such as example:Event, the pattern will be checked only for resources with example:Event type. In other words, the following graph patterns would be looked for and, if found, the violation would be raised:

?resource a example:Event.
?resource example:startDate ?start.
?resource example:endDate ?end.
FILTER (?start > ?end)

If the constraint is attached to rdfs:Resource, it is a global constraint. The check will happen for any resource that is part of the graph(s) being processed. In other words we would look for the following patterns:

?resource example:startDate ?start.
?resource example:endDate ?end.
FILTER (?start > ?end)


-----Original Message-----
From: Karen Coyle [] 
Sent: Thursday, November 20, 2014 12:55 PM
Subject: Re: Glossary for the working group

On 11/19/14 2:22 PM, Peter F. Patel-Schneider wrote:
> SPIN has a notion of global constraints. These are attached to 
> rdfs:Resource or owl:Thing and do not have to use the variable ?this. 
> They will always be executed even if no instances exist at all, and 
> could therefore be used to check arbitrary graph patterns.

Doesn't that mean that they would be used to check ALL graph patterns in the target data space? (An example would really help me here!)


Karen Coyle
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Thursday, 20 November 2014 18:43:04 UTC