Hi,
On 22/04/16 12:45, Laurent Rucquoy wrote:
Hello,
I want to manage a TDB notably to store observations which use terms
defined in an external ontology.
This ontology is defined in OWL files available on the following web page:
https://bioportal.bioontology.org/ontologies/RADLEX?p=summary
Example of OWL file used:
- 3.13.1 version :
http://data.bioontology.org/ontologies/RADLEX/submissions/36/download?apikey=8b5b7825-538d-40e0-9e9e-5ab9274a9aeb
- 3.12 version :
http://data.bioontology.org/ontologies/RADLEX/submissions/31/download?apikey=8b5b7825-538d-40e0-9e9e-5ab9274a9aeb
What is the best practice to handle the ontology use ?
My idea is to import the OWL file as a named model in my TDB whereas my
instances are stored in the default model. These instances will be linked
to the ontology through <ontology_base_uri#RIDxxxx> resources (where
RIDxxxx is the local id of terms defined in this ontology)
When I will have to reason with the ontology, I will use a 'work' model
resulting from the union of the ontology named model and the default model.
My questions:
1) Is this the right way to reason with imported ontologies (i.e. the
default model to store the instances, named models used to import different
versions of an ontology and a 'work' model resulting from the union of
default model and named model) ?
There's no "right" answer here. It'll depend on your work flow and the
sorts of queries you want to make.
That said I would suggest putting your instance data in a named graph as
well, not in the default model. That leaves you free to set "union
default" so that you can query the union of the instance and ontology data.
Note that the built-in Jena reasoners are in-memory reasoners only and
reasoning over a TDB model will be slow and not improve scaling.
2) How can I handle the different versions of OWL files ?
e.g. in one version of this ontology, the RID31872 term is identified by the
<http://www.owl-ontologies.com/Ontology1447432460.owl#RID31872> uri
while the same term is identified by the
<http://www.owl-ontologies.com/Ontology1415135201.owl#RID31872> uri
Ugh, that's completely horrible. I don't see a reasonable way you can
handle that.
As far as I can see there is no relationship between the different
versions of the term. Just because they happen to have the same
localname is irrelevant, they are different resources. Looking at those
files I see no provision for versioning - there's no unversioned
resources, no versioning links, no mapping terms, nothing. Hopefully
that's somewhere and I'm just missing it.
Unless you have some separate mapping information that isn't included in
those links then I'm afraid this is a case of "don't start from here".
Which information will be the more useful to store in my default model to
be able to link to the corresponding term in the different versions of the
ontology since the base uri could change from one version to the other
(while the local part is still the same) ?
As I say, there's just no easy way to handle that. You are dealing with
"ontologies" that have made no provision for versioning. Indeed I would
suggest you are dealing with data that started out not as an ontology
and has just been mapped to OWL syntax.
To fix that would require deep understanding of what the nature of the
changes are between those different versions.
Assuming the concepts actually have closely related meanings between the
different versions (a big assumption) then my best advice would be to
create a new URI set with unversioned URI corresponding to each concept
in the union of the ontology versions you are looking at. Use those
unversioned URIs in your instance data. Then create a set of mappings to
map your unversioned resources to the versioned ones. Precisely what
mapping terms to use depends on the detailed semantics involved.
Dave
