All DCAT resources have a :hasPolicy to reference an ODRL Policy

[joshcornejo]

Bug Report

Describe the Bug

Section 2.1

"However in the second case we are dealing with DCAT objects, that have no concept of Offers, Policies or Assets. Rather, their vocabulary includes Datasets, Dataservices etc. So when deserializing those DCAT objects there is no way to reconstruct Policy#uid, because the JSON-LD structure does not contain it."

Expected Behavior

DCAT has a property for an ODRL conformant policy expressing the rights associated with the resource.

In RDF:

md:example_catalog terms:created "2024-09-30T18:47:57.0720000Z"^^xsd:dateTime;
                        terms:description "** this is the example catalog **"@en;
                        terms:valid md:turi:225b96258645:13275I;
                        a odrl:Asset,
                          dcat:Catalog;
                        owl:versionInfo "1.0"@en;
                        odrl:hasPolicy md:policy_one,                             # <--- here are the links to the policies
                                       md:demo_offer_performance_bank_exchange,
                                       md:demo_offer_bank_exchange;
                        # all the other asset properties       
                        prov:version "1.0"@en.

[mspiekermann]

Maybe I don't get your point, in this case please just reopen the issue. But, as you described it is how it works in EDC (with Dataspace Protocol), see https://eclipse-edc.github.io/documentation/for-contributors/control-plane/entities/#6-catalog for an example.

To account for this, we defined the Policy class as value object that contains rules and other properties. In addition, we have a PolicyDefinition class, which contains a Policy and an id property, which makes it an entity

Policies are ODRL policies as stated in https://eclipse-edc.github.io/documentation/for-contributors/control-plane/entities/#2-policies.

[joshcornejo]

Hi @mspiekermann

As you established, what EDS writes:
"However in the second case we are dealing with DCAT objects, that have no concept of Offers, Policies or Assets."

Is an incorrect statement, the DCAT standard has a property for an ODRL conformant policy expressing the rights associated with the resource. (link to the standard ...)

[mspiekermann]

@joshcornejo alright, just checked the linked example and saw we mentioned the hasPolicy property for the DCAT object. I'll have a look to fix the docs.