Thing 3. Serializations

Getting Started

Once some information has been modeled using the Resource Description Framework (RDF), it needs to be expressed in a particular way so that it can be shared and used by applications or on the web. We call this form of expression a serialization, also known as a syntax. There are many different serialization formats available, each with their own pros and cons. 

Often a specific syntax will be developed by a specific community - for instance, the JSON-LD serialization is based on models used by web developers who might not be familiar with RDF to begin with. Similarly, RDF/XML uses structures familiar to anyone who has been exposed to XML, or to some extent HTML as well. Each syntax or serialization emphasizes the needs of the group that creates it, just as different measurement systems or metadata standards work for different groups and purposes. There may also be common practices of a certain community that are reflected in a serialization (e.g. always starting a document by naming its context, or using certain punctuation to open or close a statement). In this Thing, you will learn how to identify and read a few of the more common formats. 
 

Activities

Read through this list of RDF syntaxes (serializations). The table near the bottom of the W3C page shows some of the most commonly used serializations. 

• Note how the main list is organized by the base markup language or tool.
• Choose two syntaxes and click on their linked names to learn more about them. In the library Linked Data world you will most often encounter RDF/XML, JSON-LD, or Turtle, but you may look at any syntax you like for this exercise. 

Take this example sentence: Toni Morrison is the author of The Bluest Eye. Remember that in Thing 2 we split it up into three pieces:

• 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

Using this example, practice expressing this bit of RDF in each of the two syntaxes you chose.

Reflection

How does a chosen syntax change how RDF is expressed? What are some differences between the two syntaxes you chose to explore? What pieces of information are more prominent than others? Consider sharing your reflection responses in the Comments section at the bottom of the page.

Additional Resources

• “RDF 1.1 XML Syntax.” W3C Recommendations. 25 February 2014, https://www.w3.org/TR/rdf-syntax-grammar/
• JSON for Linking Data. https://json-ld.org/. Accessed 15 July 2022.
• “RDF 1.1 Turtle: Terse RDF Triple Language.” W3C Recommendations. 25 February 2014, https://www.w3.org/TR/turtle/

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