oold-python

Linked data class python package for object oriented linked data (OO-LD). This package aims to implemment this functionality independent from the osw-python package - work in progress.

Features

Code Generation

Generate Python data models from OO-LD Schemas (based on datamodel-code-generator):

from oold.generator import Generator
import importlib
import datamodel_code_generator
import oold.model.model as model

schemas = [
    {   # minimal example
        "id": "Foo",
        "title": "Foo",
        "type": "object",
        "properties": {
            "id": {"type": "string"},
        },
    },
]
g = Generator()
g.generate(schemas, main_schema="Foo.json", output_model_type=datamodel_code_generator.DataModelType.PydanticBaseModel)
importlib.reload(model)

# Now you can work with your generated model
f = model.Foo(id="ex:f")
print(f)

This example uses the built-in Generator to create a basic Pydantic model (v1 or v2) from JSON schemas.

More details see example code

Object Graph Mapping

Illustrative example how the object orient linked data (OO-LD) package provides an abstract knowledge graph (KG) interface. First (line 3) primary schemas (Foo) and their dependencies (Bar, Baz) are loaded from the KG and transformed into python dataclasses. Instantiation of foo is handled by loading the respective JSON(-LD) document from the KG and utilizing the type relation to the corresponding schema and dataclass (line 5). Because bar is not a dependent subobject of foo it is loaded on-demand on first access of the corresponding class attribute of foo (foo.bar in line 7), while id as dependent literal is loaded immediately in the same operation. In line 9 baz is constructed by an existing controller class subclassing Foo and finally stored as a new entity in the KG in line 11.

Represent your domain objects easily and reference them via IRIs or direct object instances. For instance, if you have a Foo model referencing a Bar model:

import oold.model.model as model

# Create a Foo object linked to Bar
f = model.Foo(
    id="ex:f",
    literal="test1",
    b=model.Bar(id="ex:b", prop1="test2"),
    b2=[model.Bar(id="ex:b1", prop1="test3"), model.Bar(id="ex:b2", prop1="test4")],
)

print(f.b.id)          # ex:b
print(f.b2[0].prop1)   # test3

You can also refer to objects by IRI:

# Assign IRI strings directly
f = model.Foo(
    id="ex:f",
    literal="test1",
    b="ex:b",  # automatically resolved to a Bar object
    b2=["ex:b1", "ex:b2"],
)

Thanks to the resolver mechanism, these IRIs turn into fully-fledged objects as soon as you need them.

More details see example code

RDF-Export

Easily convert your objects to RDF (JSON-LD) and integrate with SPARQL queries:

from rdflib import Graph
from typing import List, Optional

# Example: Convert Person objects to RDF
p1 = model.Person(name="Alice")
p2 = model.Person(name="Bob", knows=[p1])

# Export to JSON-LD
print(p2.to_jsonld())

# Load into RDFlib
g = Graph()
g.parse(data=p1.to_jsonld(), format="json-ld")
g.parse(data=p2.to_jsonld(), format="json-ld")

# Perform SPARQL queries
qres = g.query("""
    SELECT ?name
    WHERE {
        ?s <https://schema.org/knows> ?o .
        ?o <https://schema.org/name> ?name .
    }
""")
for row in qres:
    print("Bob knows", row.name)

The extended dataclass notation includes semantic annotations as JSON-LD context, giving you powerful tooling for knowledge graphs, semantic queries, and data interoperability.

More details see example code

Dev

git clone https://github.com/OpenSemanticWorld/oold-python
pip install -e .[dev]

Note

This project has been set up using PyScaffold 4.5. For details and usage information on PyScaffold see https://pyscaffold.org/.