Restrictions on individuals

[jesper-friis]

Individuals relating to classes should be represented as restrictions in the KB.

E.g. table where the column (i.e. keyword) is a ObjectProperty and the entry is a Class.
It will end up looking like this initially dataset1 isOutputOf Simulation, but this is not valid.

It should be:

:dataset1 a 
    dcat:Dataset ,
    [ a owl:Restriction ;
     owl:onProperty :isOutputOf ;
     owl:someValuesFrom :Simulation 
     ] .

This means that Tripper must know whether :Simulation is an individual or a class. Currently it is just assumed that they are all individuals.

Tasks:

• Figure out whether we want to relate an individual to a class by creating a blank node or via a restriction. Only possible drawback with creating an individual is that it is not easy do do in Protege.
• Add a function that queries the triplestore to check whether IRIs in a table are a class or not (alternatively query the triplestore for all classes). All classes should be added to a context object.
  This function could be called once in datadoc.store().
• Implement an datadoc.update_individuals() function that converts references to classes.

[jesper-friis]

We have two options for relating an individual :my_data to class :MyClass via the relation :hasRel:

Option 1, create a blank node :MyClass individual:

:my_data a dcat:Dataset ;
    :hasRel [ a :MyClass ] .

Option 2, create a restriction:

:my_data a dcat:Dataset ;
    rdf:type [ a owl:Restriction ;
               owl:onProperty :hasRel ;
               owl:someValuesFrom :MyClass ] .