A CatalogRecord describes an entry in the catalog. Notice that while dcat:Resource represents the dataset or service itself, dcat:CatalogRecord is the record that describes the registration of an item in the catalog. The use of dcat:CatalogRecord is considered optional. It is used to capture provenance information about entries in a catalog. If this distinction is not necessary then dcat:CatalogRecord can be safely ignored.
RDF allows resources to have global identifiers (IRIs) or to be blank nodes. Blank nodes can be used to denote resources without explicitly naming them with an IRI. They can appear in the subject and object position of a triple [[rdf11-primer]].
-While blank nodes may offer flexibility for some use cases, in a Linked Data context, blank nodes limit our ability to collaboratively annotate data. A blank node resource cannot be the target of a link and it can't be annotated with new information from new sources. As one of the biggest benefits of the Linked Data approach is that "anyone can say anything anywhere", use of blank nodes undermines some of the advantages we can gain from wide adoption of the RDF model. Even within the closed world of a single application dataset, use of blank nodes can quickly become limiting when integrating new data [[LinkedDataPatterns]].
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RDF allows resources to have global identifiers (IRIs) or to be blank nodes. Blank nodes can be used to denote resources without explicitly naming them with an IRI. They can appear in the subject and object position of a triple [[rdf11-primer]]. +While blank nodes may offer flexibility for some use cases, in a Linked Data context, blank nodes limit our ability to collaboratively annotate data. A blank node resource cannot be the target of a link and it can't be annotated with new information from new sources. As one of the biggest benefits of the Linked Data approach is that "anyone can say anything anywhere", use of blank nodes undermines some of the advantages we can gain from wide adoption of the RDF model. Even within the closed world of a single application dataset, use of blank nodes can quickly become limiting when integrating new data [[LinkedDataPatterns]]. For these reasons, instances of the DCAT main classes SHOULD have a global identifier, and use of blank nodes is generally discouraged when encoding DCAT in RDF.
All RDF examples in this document are written in Turtle syntax [[Turtle]] and are available from the DXWG code repository.