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Introduction to Linked Data for Islandora

The purpose of this page is to provide a guided reading list to anyone who wants to get up to speed on the basics of linked data within the Islandora community. Those who make their way through the readings will be able to talk competently about linked data and better understand the design decisions made in Islandora. The list starts with the fundamentals of linked data (RDF, SPARQL, serializations and ontologies) and moves toward more advanced topics specific to the use cases of a Fedora 4 based digital repository system.

Basics of Linked Data

This section seeks to give the reader a foundational understanding of what linked data is, why it is useful, and a very superficial understanding of how it works.

Understanding RDF

This section is all about RDF, the Resource Description Framework, which defines the way linked data is structured.

Querying Linked Data with SPARQL

This section takes a look at SPARQL, the query language that allows you to ask linked data very specific questions. The queryable nature of linked data is one of the things that makes it so special. Try some SPARQL queries on DBpedia's endpoint to get some hands-on experience.

RDF Serialization Formats

RDF data can be translated into many different formats. RDF/XML is the original way that RDF data was shared, but there are much more human-friendly serialization formats like Turtle which is great for beginners. JSON-LD is the easiest format for applications to use, and is the serialization format that Islandora uses internally. Make sure to check out the JSON-LD Playground for an interactive learning experience.

Ontology & Vocabulary Basics

Ontologies & vocabularies are created by communities of people to describe things, and once created, anyone can use an ontology or vocabulary to describe their resources. This section goes over some of the more popular ontologies & vocabularies in use.

Building Ontologies

One isn't limited to the ontologies & vocabularies that already exist in the world, anyone is free to create their own. This section goes over ontologies that exist to help those trying to create their own ontologies.

Repository-Specific Ontologies

Most ontologies are very specific to certain use cases, and digital repository systems are no different. This section covers ontologies that are of specific interest to users of Islandora, or any Fedora 4 based digital repository system.

Last update: April 13, 2022