Shortcomings in Drupal Taxonomy Module

As we’ve written about in detail elsewhere on this blog, we use the Taxonomy module in Drupal for the Subject field. It’s set up so that every time we enter a new subject term the term gets added to a controlled vocabulary that’s stored in Drupal. It is possible to then go into this controlled vocabulary and create a hierarchical thesaurus by setting up relationships between terms. Drupal allows you to assign related terms, broader terms, narrower terms, and “synonyms” or use for terms. However, I have not been doing this in Drupal and instead I’ve been creating a thesaurus in a separate thesaurus software program. Yes, it means entering the terms twice, but I do it because I find the taxonomy module in Drupal to be limited in the following ways:

  1. When you enter a non-preferred term (which in Drupal is called a synonym), the non-preferred term is only noted under the preferred term as a synonym and does not have a separate entry in the vocabulary list. This means that if a person wants to look up the term “contraception” and we’ve used the term “birth control,” the person will not find “contraception” in the alphabetical list of terms but instead only by finding “birth control” first and seeing the other term below it or through using the Find (Control F) feature, which I think a lot of people won’t think to do. In other words, Drupal has “use for” terms but not “use” terms.
  2. When you add a term as a narrower term of another term, the narrower term only gets listed under the broader term and does not have its own entry. Thus, a similar situation arises as above when someone tries to find the narrower term in the alphabetical list.

One solution to this would be to alter the program code so that synonyms and narrower terms have their own entries in the list, but apparently this is complicated. Another solution would be to build a feature into our Drupal system that would allow you to search terms only on the thesaurus page. We haven’t tried this yet. We’ve also discussed not having broader and narrower terms and only related terms, which I think would work for our purposes. There would still be the problem of the synonyms, though. One day I would like to be able to use Drupal to construct the zine thesaurus, but for now I’ll keep using the thesaurus software program THEW32. It allows me to export the thesaurus in HTML, so I’ve been posting it as a separate page in the catalogue with the terms hyperlinked. The interface for setting up relationships between terms and editing terms in THEW32 is better than Drupal, so perhaps it would take me just as long to make my thesaurus in Drupal as it takes to transfer subject terms to my thesaurus in THEW32.

Here is the thesaurus I’m creating in THEW32 and here is the flat list of subject terms in Drupal. You can see where I set up a few relationships in Drupal to see how they displayed. So much more could be done with the Drupal Taxonomy module, and if I were a Drupal developer I would do it! It would be wonderful if when a cataloguer or searcher entered a non-preferred term, the preferred term was automatically suggested to them. It would be awesome if you could easily search a single controlled vocabulary. I hope it will be improved in the future.