Beginning Drupal 8

Chapter 4
Taxonomy
One of the Drupal features new Drupal users underuse and misunderstand is taxonomy. New Drupal users
are overwhelmed with all of the other features and functions provided by the platform, and they bypass what
may be one of the most powerful and useful features that Drupal has to offer. In this chapter you will create
and use taxonomy terms to categorize content so that visitors can easily find information related to a
specific topic.
Taxonomy Overview
While many of us may not be able to define the word “taxonomy,” the reality is that we use taxonomy on a
daily basis as a means for categorizing “things” in our lives. If you open the doors to your kitchen pantry,
you might find an orderly assemblage of food items: all of your spices on the top shelf, canned food on the
second shelf, pastas and other boxed foods on the third shelf, and cereal boxes on the fourth. Categorizing
your food items and putting things away in an orderly fashion so that you can easily find food items when
you need them to prepare a meal is in its simplest form the use of taxonomy. Without this “kitchen taxonomy
system,” you may have everything you need to make dinner jammed randomly in the pantry, but finding it
may be a challenge, leading to frustration and a phone call to the local pizza delivery restaurant when you’re
not able to find the ingredients you need to make a meal.
In Drupal, taxonomy is divided into two general capabilities: tagging and structured taxonomy. Both are
powerful solutions and can be used simultaneously on your site. Tagging is a simplified yet powerful use of
the taxonomy system, enabling content authors to enter keywords that describe the content in a text field on
the content editing form. As an example of tagging content, an author who writes an article about alternative
energy could use keywords, or tags, such as “solar,” “wind,” and “geothermal” to categorize the article. The
keywords created by the author are typically displayed as hyperlinks at the end of the article and can be used
by site visitors to locate other content tagged with the same keywords.
Tagging is freeform, meaning it’s up to the author to define what words they want to use to classify their
content. A common issue with using tagging as an approach to categorize content is that different people
use different words to refer to the same concept. For example, an article about rain might be tagged with the
word “rain” by one author, “precipitation” by another author, and “drizzle” by a third. Site visitors trying to
find articles about the general concept of rain would have a difficult time finding the ones tagged with words
other than “rain.” Another common problem is misspellings. If an author tags an article about rain with
“reign,” then site visitors are going to have a hard time, using taxonomy, to find that article using the
word “rain.”
The second approach for using taxonomy to categorize content in Drupal is structured taxonomy. In
this approach, a site administrator creates all the words that can be used to categorize content, and content
authors simply select from the list of words to categorize their content. A benefit of structured taxonomy
is that it can be hierarchical, meaning terms may be put into groups to categorize content. An example
of a hierarchy could be taxonomy for sports. The first level of terms could be “team sports” and
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