How to not duplicate classes to have optional id ?

[ticapix]

Hello,

Is there a way to declare a classes to have an optional id or a simpler workaround than the one below ?

My Linkml schema Person.yaml file:

id: example-schema
name: ExampleSchema
description: An example schema demonstrating a class with a slot mapped to foaf:name.
prefixes:
  linkml: https://w3id.org/linkml/
  foaf: http://xmlns.com/foaf/0.1/
  example: http://example.org/
default_prefix: example
default_range: string

imports:
  - linkml:types

classes:
  DocumentBlank:
    class_uri: foaf:Document
    slots:
      - topic

  Document:
    is_a: DocumentBlank
    class_uri: foaf:Document
    slots:
      - id

  Person:
    description: A person entity with a name.
    class_uri: foaf:Person
    slots:
      - id
      - name
      - publications

slots:
  id:
    identifier: true
    range: uriorcurie
  name:
    slot_uri: foaf:name
  topic:
    slot_uri: foaf:topic
  publications:
    domain: Person
    slot_uri: foaf:publications
    range: DocumentBlank
    multivalued: true

I generate the python code with gen-python Person.yaml > Person.py

And I use it as below:

#!/usr/bin/env python3
from pathlib import Path
from linkml_runtime.dumpers import RDFLibDumper
from linkml_runtime.utils.schemaview import SchemaView
import Person

if __name__ == "__main__":
    doc = Person.Document(id="example:doc2", topic="doc2")

    p1 = Person.Person(id="example:p1",
                             name="foobar",
                             publications=[
                                 Person.DocumentBlank(topic="doc1"), doc
                             ])

    schema_view = SchemaView(Path(__file__).parent / 'Person.yaml')

    g = RDFLibDumper().as_rdf_graph(element=p1, schemaview=schema_view)
    print(g.serialize())

To finaly get

@prefix example: <http://example.org/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .

example:p1 a foaf:Person ;
    foaf:name "foobar" ;
    foaf:publications [ a foaf:Document ;
            foaf:topic "doc1" ],
        example:doc2 .

example:doc2 a foaf:Document ;
    foaf:topic "doc2" .

Is there a simple way, without having to duplicate class with a "dummy" DocumentBlank class ?

Thank you
Pierre

[OlivierTiratCDE]

Tu as réussi a créer un blank node. Ton document doc1 n'a pas d'id il référence bien un blank_node. Bien sur tous les "objets" avec un id ne peuvent pas être des blank node puisqu'ils doivent avoir un id ;)
Les seules classes pouvant données lieu à des blank node n'ont pas d'id.

Pour l'histoire des types multiples, je crois qu'ils s'obtiennent essentiellement par l'héritage et que la gestion dans linkml n'est pas bonne. J'ai du adapté les choses en faisant dériver tout d'un objet unique qui corrige les defauts. On peut faire autrement en adapatant le système de génération de code je crois, mais je ne suis pas rentrer la dedans pour le moment.

[vincentkelleher]

@ticapix I had a closer look at the LinkML data model and the Python generator. It is easier to just remove the identifier: true and replace it with required: false at the moment.

Whether it is in the LinkML Runtime SchemaView or in the multiple generators, an identifier has to be provided and changing that behavior seems sketchy.

IMHO, I would suggest renaming your slot to url for example and just use it as a basic attribute. You could also keep the id as it is and force developers/users to provide an ID even if it is "virtual" just like you would do with a verifiable credential using a non-resolvable ID 😇