On 4/15/2015 9:46, Karen Coyle wrote:
> Holger, is this explanation solely SPARQL specific? If so, if SPARQL
> is not being used, what is the meaning of dataset? Is as Corey defined?
Direct pick-and-choose access to named graphs is indeed only relevant
for SPARQL, via GRAPH or FROM keywords. If you have generic constraints
such as checking the cardinality of a property and the properties are
distributed across multiple named graphs, then the "default graph" of
the dataset would be used, and that could very well be the union of
multiple graphs.
> And I'm not sure how graph "implementations" can be wrappers of remote
> graphs. This may be important for us, as we do have the issue of of
> needing to access external graphs to complete validation.
This is a fairly technical topic, and I was referring to Jena
implementations and interfaces. Jena does have adapters (Graph
implementations) for all kinds of databases from different vendors. It
is also straight-forward to create a Graph implementation that delegates
all queries to a SPARQL end point. Optimizations of this access are IMHO
implementation-specific and can be handled by a SHACL engine and the
Dataset implementation. Likewise, a SHACL engine could modify the
default SPARQL queries that it gets so that they have better performance
(e.g. inlining sh:allowedValues).
Holger
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