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TopHow To Structure Data
The data on the Web of Data is called metadata. Metadata is structured data that uses different metadata schemas (or vocabularies) to describe resources. Next sub-sections will guide the reader through the concepts of metadata and metadata schemas, and will present three different metadata schemas that can be used to describe particular contexts of e-commerce: the Good Relations ontology, the ESSGlobal vocabulary and the schema.org ontology.
Key Terms in this Chapter
RDF Serialisation: A way to formalise metadata records, i.e. a way for machines to read and process information. The most common serialisations are RDF/XML and Turtle.
Good Relations: Good Relations is a ontology for describing many aspect of the context of application of e-commerce.
Resource Description Framework (RDF): RDF is a framework that includes a data model and a general-purpose language to describe metadata. This data model is based on a conceptual idea made of triples, each consisting of a subject, a predicate and an object.
Metadata Schema: A metadata schema is a set of metadata elements, their relations and constraints, defined with a specific goal, in a specific context. A metadata schema is also known as “vocabulary” or “RDF vocabulary”.
Metadata Application Profile: A metadata application profile is a generic construct for designing metadata records. An Application profile is a combination of different metadata schemas optimised for a certain context of application. A community of practice that uses the same Application Profile enhances semantic interoperability among its agents.
Metadata: Metadata is data about data, structured data about a resource that represents a tangible or non-tangible thing. A thing is anything that one wants to describe: it can be a real object such a book or a conceptual entity such as a service.
Ontology: In philosophy this term means “the study of the nature of the being, becoming, existence, and reality as well as the basic categories of the being and their relations” (source: Wikipedia). In the Web of Data an Ontology is a complex metadata schema that describes a reality or a context, expressing the categories of resources and their relations.
ESSGlobal: ESSGlobal is a metadata schema, referred as an RDF vocabulary, for describing many aspects of the context of application of Social and Solidarity Economy.
Metadata Element: A metadata element, also known as term, property or attribute belongs to a specific metadata schema. It is used to describe a specific property of a resource like, title of a book or name of a person.
Web of Data: The Web of Data is made of structured data read by agents that relate structured data located in servers through the existence of links – this data is also called Linked Data since it is data connected through links. The data that exists in the Web of Data is called metadata.