GitHub user jessehatfield opened a pull request:
https://github.com/apache/incubator-rya/pull/201
RYA-295 owl:allValuesFrom inference
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## Description
Inference applies owl:allValuesFrom semantics for queries including
statement patterns of the form "?x rdf:type :DefinedClass".
An owl:allValuesFrom property restriction is a universal class expression:
it defines type T1 to be the set of individuals such that, for a given property
p and type T2, all values of that property (i.e. all objects of triples where
the predicate is p and the subject belongs to T1) have type T2. Therefore, if
an individual is known to belong to the universal class expression (T1), then
it can be inferred that all of its values for the property belong to the value
type (T2). This is similar to rdfs:range except that it only applies when the
subject of the triple belongs to the appropriate class expression.
InferenceEngine, at refresh time, stores information about
owl:allValuesFrom restrictions (universal class expressions). These definitions
can then be accessed by the value type: getAllValuesFromByValueType(<value
type>) returns every (restriction type, property) pair.
AllValuesFromVisitor processes statement patterns of the form "?x rdf:type
:T2", and if :T2 is the value type for any owl:allValuesFrom restriction
according to the inference engine, it replaces the statement pattern with a
union: of 1) that same statement pattern (in case the type is explicitly
asserted or can be inferred by some other rule); and 2) a subquery of the form
"?y \:p ?x . ?y rdf:type :T1" for the appropriate (restriction type, property)
pair.
RdfCloudTripleStoreConnection calls the visitor along with the other
inference logic. Because the original statement pattern is preserved as one
branch of the union, other visitors can still apply if there are other ways to
derive the type.
Added a simple example of a query that relies on this inference to
MongoRyaDirectExample.
### Tests
Unit test to verify that InferenceEngine stores and returns the schema;
unit test to verify that AllValuesFromVisitor rewrites queries of the proper
form; integration test to verify correct results for sample
ontology+instances+query relying on allValuesFrom inference.
### Links
[Jira](https://issues.apache.org/jira/browse/RYA-295)
### Checklist
- [ ] Code Review
- [ ] Squash Commits
#### People To Reivew
@ejwhite922
@isper3at
@meiercaleb
@pujav65
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/jessehatfield/incubator-rya
RYA-295-allValuesFrom-inference
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-rya/pull/201.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #201
----
commit 55eae37e2f4aaef2f8cd41c735241c2ae85b88af
Author: Jesse Hatfield <[email protected]>
Date: 2017-08-08T19:58:10Z
RYA-295 owl:allValuesFrom inference
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