About Thing 2
Purpose: Resource Description Framework (RDF) is the standard structure used to model data and enable it to be shared and used across the Web. Uniform Resource Identifiers (URIs) are specific, unique strings that are used to specify information in a machine-readable and actionable way.
Learning Outcomes: Understand the three-part structure of RDF and why it is important to Linked Data.
Define a URI and understand what makes them useful in Linked Data applications.
Intended Audience: Beginner
Author: Lizzy Baus, Macalester College
Expected Duration: 45-60 minutes
This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.
Getting Started
In Thing 1, you learned about what Linked Data is and why it is useful and important. The next step in making it a reality is learning how it actually works. One main component of that is Resource Description Framework (RDF), which is the standard model for expressing information. RDF is not a language like HTML, but it does have a grammar structure. RDF takes each piece of information and breaks it into three parts: the subject, the predicate, and the object. These are put together to form what’s called a triple. You can think of it like a sentence.
Here’s an example:
- Subject | what the triple is about | Toni Morrison
- Predicate | what the relationship is (like a verb) | is the author of
- Object | the other half of the relationship | The Bluest Eye
So put together, this RDF triple gives us: Toni Morrison is the author of The Bluest Eye. Since RDF is a standard, widely-used model, many applications and systems can make sense of this triple structure.
A Uniform Resource Identifier (URI) makes these triples even more useful - it makes things specific and unambiguous. Each URI refers to one and only one thing, so you will not find a case where two things use the same URI. This means that any user, human or machine, can with certainty know what is being referred to by each piece of data in the RDF they’re looking at. You have probably heard of a URL (Uniform Resource Locator), which is what appears in the address bar as you navigate around the internet. A URL is one type of URI that can be used by web browser programs; there are other kinds of URIs that work in other contexts.
Activities
Videos
Watch this 7-minute video on RDF, which also touches on URIs (and previews Thing 3. Serializations!)
Readings
- Read sections 1 through 3 of the RDF 1.1 Concepts and Abstract Syntax specification.
- Explore the diagrams made by different RDF Data Visualization tools.
- Read about Cool URIs and what makes them most useful in sections 4.5 and 4.6.
Reflection
Think about how the information you work with could be described using RDF. How would you represent the information in a MARC field using triple structures? Consider sharing your reflection responses in the Comments section at the bottom of the page.
Additional Resources
- PCC URI Task Group on URIs in MARC. URI FAQs. Program for Cooperative Cataloging, September 26, 2018. www.loc.gov/aba/pcc/bibframe/TaskGroups/URI FAQs.pdf
Claim Credit
Need a certificate of completion? Answer the questions below, submit them, and you’ll receive an email confirmation with a link to download your certificate.
The film The Maltese Falcon / was directed by / John Huston
The film The Maltese Falcon / was written by / John Huston
The film The Maltese Falcon / was produced by / Warner Bros. Pictures
The film The Maltese Falcon / was produced in / 1941
The book the Maltese Falcon / was written by / Dashiell Hammett
Humphrey Bogart / acted in / the film The Maltese Falcon
Was'nt sure if IRIs or URIs were required for this, so took the literal string route.
Think about how the information you work with could be described using RDF. How would you represent the information in a MARC field using triple structures?