Part 2: Adding Relationships

So far we have made a simple subsumption hierarchy with minimal metadata on each class

We will now extend the model to include relationships, modeled using existential restriction axioms. Specifically, we will add some pizza classes and relate them to toppings via a hasToppings relationships.

Model

pizza02-hasToppings-model.yaml

id: http://www.co-ode.org/ontologies/pizza/2005/10/18/pizza.owl
name: Pizza-Ontology-Metamodel
prefixes:
  pizza: http://www.co-ode.org/ontologies/pizza/2005/10/18/pizza.owl#
  linkml: https://w3id.org/linkml/
  dcterms: http://purl.org/dc/terms/
default_curi_maps:
    - semweb_context
default_prefix: pizza
imports:
  - linkml:types

classes:

  ## ---
  ## this class is introduced here
  ## ---
  NamedPizza:
    annotations:
      owl: Class
    attributes:
      ## ---
      ## these attributes are the same as for PizzaTopping
      ## ---
      id:
        identifier: true
        range: uriorcurie
      label:
        annotations:
          owl: AnnotationAssertion
        slot_uri: rdfs:label
      conforms_to:
        annotations:
          owl.fstring: AnnotationAssertion( dcterms:conformsTo {id} pizza:{V} )
        slot_uri: dcterms:conformsTo
        designates_type: true
      subClassOf:
        annotations:
          owl: SubClassOf
        slot_uri: rdfs:subClassOf
        range: NamedPizza

      ## ---
      ## this attribute is unique to NamedPizza
      ## ---
      hasToppings:
        annotations:
          owl: ObjectSomeValuesFrom
        multivalued: true
        range: PizzaTopping
  ## ---
  ## copied from part 1
  ## ---
  PizzaTopping:
    attributes:
      id:
        identifier: true
        range: uriorcurie
      label:
        annotations:
          owl: AnnotationAssertion
        slot_uri: rdfs:label
      conforms_to:
        annotations:
          owl.fstring: AnnotationAssertion( dcterms:conformsTo {id} pizza:{V} )
        slot_uri: dcterms:conformsTo
        designates_type: true
      subClassOf:
        annotations:
          owl: SubClassOf
        slot_uri: rdfs:subClassOf
      hasToppings:
        singular_name: hasTopping
        range: PizzaTopping
        multivalued: true
        annotations:
          owl: ObjectSomeValuesFrom

Note that we have some repetition in the schema, with the same information about the same attribute repeated in both NamedPizza and PizzaTopping (although note the difference in range for subClassOf in both classes). We will return to address this issue later.

Here we introduce a new slot/attribute hasToppings. This has an interpretation of ObjectSomeValuesFrom

Data

Our new data file now has two kinds of records: PizzaToppings and NamedPizzas:

pizza02-hasToppings-data.yaml

# named pizzas
- id: pizza:NamedPizza
  conforms_to: NamedPizza
  label: named pizza

- id: pizza:Mushroom
  conforms_to: NamedPizza
  label: mushroom
  subClassOf: pizza:NamedPizza
  hasToppings:
    - pizza:MozzarellaTopping
    - pizza:MushroomTopping
    - pizza:TomatoTopping
- id: pizza:Margherita
  conforms_to: NamedPizza
  label: Margherita
  subClassOf: pizza:NamedPizza
  hasToppings:
    - pizza:MozzarellaTopping
    - pizza:TomatoTopping

# toppings
- id: pizza:FishTopping
  label: fish topping
  conforms_to: PizzaTopping
  subClassOf: pizza:PizzaTopping
- id: pizza:MeatTopping
  label: meat topping
  conforms_to: PizzaTopping
  subClassOf: pizza:PizzaTopping
- id: pizza:VegetableTopping
  label: vegetable topping
  conforms_to: PizzaTopping
  subClassOf: pizza:PizzaTopping
- id: pizza:CheeseTopping
  label: cheese topping
  conforms_to: PizzaTopping
  subClassOf: pizza:PizzaTopping

- id: pizza:PepperoniSausageTopping
  label: pepperoni sausage topping
  conforms_to: PizzaTopping
  subClassOf: pizza:MeatTopping

- id: pizza:AnchoviesTopping
  label: anchovies topping
  conforms_to: PizzaTopping
  subClassOf: pizza:FishTopping

- id: pizza:ArtichokeTopping
  label: artichoke topping
  conforms_to: PizzaTopping
  subClassOf: pizza:VegetableTopping

- id: pizza:MushroomTopping
  label: mushroom topping
  conforms_to: PizzaTopping
  subClassOf: pizza:VegetableTopping

- id: pizza:TomatoTopping
  label: tomato topping
  conforms_to: PizzaTopping
  subClassOf: pizza:VegetableTopping

- id: pizza:MozzarellaTopping
  label: mozzarella topping
  conforms_to: PizzaTopping
  subClassOf: pizza:CheeseTopping

Note the hasToppings slot is multivalued, so this is specified as a list.

Output

pizza02.ofn:

Ontology( <http://www.co-ode.org/ontologies/pizza/2005/10/18/pizza.owl>
    AnnotationAssertion( rdfs:label pizza:Mushroom "mushroom" )
    AnnotationAssertion( dcterms:conformsTo pizza:Mushroom pizza:NamedPizza )
    SubClassOf( pizza:Mushroom     ObjectSomeValuesFrom( pizza:hasToppings pizza:MozzarellaTopping ) )
    SubClassOf( pizza:Mushroom     ObjectSomeValuesFrom( pizza:hasToppings pizza:MushroomTopping ) )
    SubClassOf( pizza:Mushroom     ObjectSomeValuesFrom( pizza:hasToppings pizza:TomatoTopping ) )
    AnnotationAssertion( rdfs:label pizza:Margherita "Margherita" )
    AnnotationAssertion( dcterms:conformsTo pizza:Margherita pizza:NamedPizza )
    SubClassOf( pizza:Margherita     ObjectSomeValuesFrom( pizza:hasToppings pizza:MozzarellaTopping ) )
    SubClassOf( pizza:Margherita     ObjectSomeValuesFrom( pizza:hasToppings pizza:TomatoTopping ) )
    AnnotationAssertion( rdfs:label pizza:FishTopping "fish topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:FishTopping pizza:PizzaTopping )
    SubClassOf( pizza:FishTopping pizza:PizzaTopping )
    AnnotationAssertion( rdfs:label pizza:MeatTopping "meat topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:MeatTopping pizza:PizzaTopping )
    SubClassOf( pizza:MeatTopping pizza:PizzaTopping )
    AnnotationAssertion( rdfs:label pizza:VegetableTopping "vegetable topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:VegetableTopping pizza:PizzaTopping )
    SubClassOf( pizza:VegetableTopping pizza:PizzaTopping )
    AnnotationAssertion( rdfs:label pizza:CheeseTopping "cheese topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:CheeseTopping pizza:PizzaTopping )
    SubClassOf( pizza:CheeseTopping pizza:PizzaTopping )
    AnnotationAssertion( rdfs:label pizza:PepperoniSausageTopping "pepperoni sausage topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:PepperoniSausageTopping pizza:PizzaTopping )
    SubClassOf( pizza:PepperoniSausageTopping pizza:MeatTopping )
    AnnotationAssertion( rdfs:label pizza:AnchoviesTopping "anchovies topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:AnchoviesTopping pizza:PizzaTopping )
    SubClassOf( pizza:AnchoviesTopping pizza:FishTopping )
    AnnotationAssertion( rdfs:label pizza:ArtichokeTopping "artichoke topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:ArtichokeTopping pizza:PizzaTopping )
    SubClassOf( pizza:ArtichokeTopping pizza:VegetableTopping )
    AnnotationAssertion( rdfs:label pizza:MushroomTopping "mushroom topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:MushroomTopping pizza:PizzaTopping )
    SubClassOf( pizza:MushroomTopping pizza:VegetableTopping )
    AnnotationAssertion( rdfs:label pizza:MozzarellaTopping "mozzarella topping" )
    AnnotationAssertion( dcterms:conformsTo pizza:MozzarellaTopping pizza:PizzaTopping )
    SubClassOf( pizza:MozzarellaTopping pizza:CheeseTopping )

In Protege: