Controlled Vocabularies and Authority Control in DSpace 7

How this worked in DSpace 6

Three concepts:

• Authority control values tend to be external. It was originally designed to search external sources like Library of Congress or SHERPA Romeo
• Controlled vocabularies tend to be internal. They exist in a configuration subfolder with a specific XML schema: https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/controlled-vocabularies/
  • Samples include SRSC: https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/controlled-vocabularies/srsc.xml
• Value-Pairs are a "controlled vocabulary" like concept that exist only in the submission configuration (input-forms.xml): https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/input-forms.xml#L236
  • Samples include "common_identifiers" (URI, ISSN, ISBN, etc), "common_types" (Article, Book, Image, Video), "common_iso_languages" (en, es, de, fr, etc)

Default settings:

1. Value-pairs were always enabled and act like a simply form of controlled vocabulary.  They were only used to populate dropdowns in submission.
2. Additional controlled vocabularies were disabled by default. Though they could be enabled for JSPUI only: https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/dspace.cfg#L1809
3. Authority control was also disabled by default, though a variety of plugins were available out-of-the box for Library of Congress, SHERPA Romeo and ORCID: https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/dspace.cfg#L1432-L1437
   1. It was also possible to optionally configure Authority Control to use value-pairs and/or controlled vocabularies.  See https://github.com/DSpace/DSpace/blob/dspace-6_x/dspace/config/dspace.cfg#L1462-L146
      
      1. When enabled, both value-pairs and controlled vocabularies could be used as authority control on a specific field(s).

How this is working in DSpace 7.0 beta2

1. (Same/Similar behavior) Value-pairs are still always enabled in the new submission-forms.xml: https://github.com/DSpace/DSpace/blob/master/dspace/config/submission-forms.xml#L1130
2. (Different behavior) Additional controlled vocabularies are enabled by default, as they are configured to be used in Authority Control: https://github.com/DSpace/DSpace/blob/master/dspace/config/dspace.cfg#L1483
3. (Different behavior) Authority control is enabled by default, and defaults it using both value-pairs and controlled vocabularies: https://github.com/DSpace/DSpace/blob/master/dspace/config/dspace.cfg#L1481-L1483
4. (Different behavior) The Submission configuration/UI now only uses Authority Control for dropdowns, as both value-pairs and controlled vocabularies are authority control enabled.  See early notes at Configuration changes in the submission process
   1. (Same/Similar behavior) Controlled Vocabularies can be associated with a field via the <vocabulary> tag in submission-forms.xml: https://github.com/DSpace/DSpace/blob/master/dspace/config/submission-forms.xml#L202
   2. (Same/Similar behavior) Value-pairs can be associated with a field via the <input-type value-pairs-name="name">dropdown</input-type> tag. For example: https://github.com/DSpace/DSpace/blob/master/dspace/config/submission-forms.xml#L180

These behaviors primarily changed in https://github.com/DSpace/DSpace/pull/1852/

Side effects of new behavior in 7.0 beta2

1. Because all value-pairs and controlled vocabulary are authority controlled by default, all metadata fields generated from either now have "authority IDs".  This makes them look/act different from DSpace 6 metadata.
   1. For value-pairs, the authority ID is the stored value.  So, e.g. "Book" has an authority ID of "Book". See examples in REST Contract: https://github.com/DSpace/Rest7Contract/blob/master/authorities.md#authority-entry-values
   2. This will have a side effect for some other tools. 
      1. For example, Batch Metadata Editing separates authorities from values via a "::".  So, a dc.type value of "Book" will now appear as "Book::Book" in a CSV exported spreadsheet (whereas it used to appear just as "Book")
2. The Authority ID doesn't add any additional information to the field. In fact, it's not a unique Identifier.  As a basic example, both the value-pairs for "common_identifiers" and "common_types" include an "Other" option.  So a value linking to Authority ID "Other" cannot be mapped back to its source without finding the "submission-form.xml" which was used to create it (and that configuration may have been modified since then).
   1. This behavior was identical in DSpace 6, if you used value-pairs as Authority Control.  But, as noted above, this feature was disabled by default.