ICT:D Taxonomy - Vocabulary - Terms use

Using Taxonomy for Keywords and Search in Drupal (Assets, Views, Entity Browser)

Purpose

This document describes how to use **taxonomy (vocabularies and terms)** in Drupal to:

• assign multiple keywords to entities (Assets, Persons, Objects, etc.)
• reuse keywords consistently
• enable effective searching via **Combined fields filters** in Views and Entity Browser modals
• scale to large datasets (1000+ entities)

No custom code is required.

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Concepts (short definitions)

Term	Meaning in Drupal
Taxonomy	The classification system
Vocabulary	A named set of related terms (e.g. "Keywords")
Term	One keyword inside a vocabulary

A **vocabulary is part of taxonomy**, not a separate concept.

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Creating a Keyword Vocabulary

1. Go to

  Structure → Taxonomy → Add vocabulary

2. Example:

  * Name: Keywords
  * Description: Free or controlled keywords for Assets and related entities

3. Save

You may create **multiple vocabularies** if needed, e.g.:

• Subject keywords
• Object type
• Period
• Location
• Technique / Material

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Adding Keywords to an Entity Type

Repeat for each entity type that needs keywords (Asset, Person, Object, etc.).

1. Go to

  Structure → Content types → Asset → Manage fields

2. Add a new field:

  * Field type: Term reference
  * Reference type: Taxonomy term

3. Field settings:

  * Allowed vocabulary: Keywords
  * Cardinality: Unlimited

4. Widget:

  * Autocomplete (tags style)

5. Save

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Keyword Usage by Editors

With autocomplete (tags style):

• Editors can **select existing keywords**
• Editors can **create new keywords on the fly** by typing and pressing Enter
• New terms are automatically added to the vocabulary
• Existing entities can be edited later to add or remove keywords

(Requires permission: Create terms in Keywords vocabulary.)

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Using Keywords in Views (Search)

Basic rule

The **Combined fields filter** can search:

• any field that is present in the View’s Fields list
• even if the field is excluded from display

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Configuring a View for Keyword Search

1. Edit the View (e.g. Entity Browser View) 2. Under Fields:

  * Add the keyword field (term reference)
  * Enable Exclude from display

3. Repeat for any other searchable fields (title, identifier, description, etc.)

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Adding the Combined Fields Filter

1. Under Filter criteria → Add 2. Choose:

  * Global: Combine fields filter

3. Expose the filter 4. In filter settings:

  * Select all searchable fields (including hidden keyword fields)

5. Save

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How the Combined Fields Filter Works

• One search box
• OR logic across fields
• Example logic:

  Title OR Identifier OR Keywords OR Description
  

There is:

• no AND syntax
• no multi-filter UI in Entity Browser modals
• only one exposed filter is shown

This is a known Entity Browser limitation.

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Scaling to Large Datasets

For large collections (1000+ Assets):

• Rich keyword metadata is essential
• Multiple vocabularies are recommended
• Combined search enables progressive narrowing:

  map 1850 Antwerp manuscript
  

This approach:

• avoids scrolling
• avoids complex UI
• remains performant
• requires no custom module

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Recommended Pattern (Summary)

Requirement	Solution
Multiple keywords per entity	Term reference field (unlimited)
Reusable keywords	Taxonomy vocabulary
Free keyword creation	Autocomplete (tags)
Narrowing search	Combined fields filter
Entity Browser modal	Single exposed combined filter
No custom code	Configuration only

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Notes for Maintainers

• Taxonomy vocabularies can be reused across entities
• Keyword structure can evolve over time
• Existing entities are not locked to initial keywords
• This setup intentionally avoids custom modules for maintainability

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