Mngr at 19:29, 27 March 2026

2026-03-27T19:29:31Z

Mngr: Created page with "= Drupal: Linking Assets to Persons (MM Relationship Without Custom Code) = == Purpose == This page documents the step‑by‑step implementation of a many‑to‑many–style relationship between Person and Asset entities in Drupal 11.x. The objective is to allow editors to: * link existing Assets to a Person, * manage these links in a table‑based UI, * search and select Assets via a modal browser, * avoid custom modules and custom database tables. This solutio..."

2026-03-27T19:22:33Z

Created page with "= Drupal: Linking Assets to Persons (MM Relationship Without Custom Code) = == Purpose == This page documents the step‑by‑step implementation of a **many‑to‑many–style relationship between Person and Asset entities** in Drupal 11.x. The objective is to allow editors to: * link existing Assets to a Person, * manage these links in a table‑based UI, * search and select Assets via a modal browser, * avoid custom modules and custom database tables. This solutio..."

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= Drupal: Linking Assets to Persons (MM Relationship Without Custom Code) =

== Purpose ==
This page documents the step‑by‑step implementation of a **many‑to‑many–style
relationship between Person and Asset entities** in Drupal 11.x.

The objective is to allow editors to:
* link existing Assets to a Person,
* manage these links in a table‑based UI,
* search and select Assets via a modal browser,
* avoid custom modules and custom database tables.

This solution uses **standard Drupal mechanisms** and is upgrade‑safe.

---

== Design Principles ==
* Prefer configuration over code
* Avoid custom schema and join tables
* Use Drupal’s entity reference system
* Use contrib modules for UX, not data modeling
* Ensure maintainability and handover safety

---

== Conceptual Model ==

{| class="wikitable"
! Entity !! Role
|-
| Person || Main entity (e.g. historical person)
|-
| Asset || Reusable referenced entity (documents, images, objects, etc.)
|}

Relationship:
* One Person → many Assets
* One Asset → many Persons (implicit)

Drupal handles this naturally via **entity references**.

---

== Required Modules ==
Ensure the following modules are enabled:

* Core:
** Field
** Views
* Contrib:
** Inline Entity Form (IEF)
** Entity Browser

No custom module is required.

---

== Step 1: Create the Entity Reference Field ==

On the **Person** entity:

1. Go to:
<pre>
Structure → Content types → Person → Manage fields
</pre>

2. Add a new field:
* Field type: '''Entity reference'''
* Label: <code>Assets</code>
* Machine name: <code>field_assets</code>

3. Reference settings:
* Target type: <code>Asset</code>
* Allowed bundles: select relevant Asset bundles
* Cardinality: '''Unlimited'''

Save the field.

---

== Step 2: Configure the Form Widget (Critical Step) ==

1. Go to:
<pre>
Manage form display
</pre>

2. For <code>field_assets</code>, select widget:
* '''Inline Entity Form – Complex'''

3. Open the widget settings (gear icon):

* ✅ Allow users to add existing entities
* ❌ Allow users to add new entities
* Entity Browser: select the Asset browser (configured in Step 3)

4. Save the form display.

'''Important:'''
Do NOT select “Entity Browser” as the field widget itself.
That widget does not provide a table‑based UI.

---

== Step 3: Create the Entity Browser for Assets ==

1. Go to:
<pre>
Configuration → Content authoring → Entity Browser
</pre>

2. Create a new browser:
* Name: <code>asset_browser</code>
* Display: Modal
* Selection mode: Multi‑select

3. Add a widget:
* Widget type: View

4. Create or select a View:
* Base table: Asset
* Display type: Entity Browser
* Pagination: 10–25 items per page
* Exposed filters:
- Title
- Type / taxonomy (as needed)
* Fields:
- Thumbnail (image style)
- Title
- Optional metadata

5. Save the Entity Browser.

---

== Step 4: Resulting Editor UX ==

On the Person edit form:

* Assets are displayed in a table
* Editors can:
- Add existing Assets
- Remove Assets
- Reorder Assets
* Clicking “Add existing Asset” opens a modal browser
* Assets are searched and selected visually

This provides a historian‑friendly workflow.

---

== Step 5: UX Cleanup – Hide the Misleading “Add node” Button ==

Inline Entity Form displays an intermediate chooser containing an
“Add node” button, which is misleading when creation is disabled.

This is hidden via Gin admin CSS.

=== CSS Location ===
<pre>
sites/default/files/gin-custom.css
</pre>

=== CSS Rule ===
<syntaxhighlight lang="css">
/* Hide misleading "Add node" button in Inline Entity Form chooser */
input.ief-entity-submit[data-drupal-selector*="ief-reference-save"][value="Add node"] {
display: none !important;
}
</syntaxhighlight>

This solution:
* requires no JavaScript
* survives AJAX rendering
* is upgrade‑safe
* does not depend on dialog wrappers

---

== Why No Join Table Was Used ==
An experimental approach using a “real” join table was evaluated and rejected because:

* it required a custom module
* it required schema lifecycle management
* UI construction required many hooks
* upgrades would require maintenance work

Drupal’s entity reference system already models the relationship correctly.

---

== Performance Notes ==
* 1000+ Assets are handled without issue
* Only referenced Assets are rendered on the Person form
* Entity Browser uses pagination and indexed Views
* Thumbnails should always use image styles

---

== Summary ==
This implementation achieves:

* ✅ Many‑to‑many relationship semantics
* ✅ Clean table‑based UI
* ✅ Visual asset selection
* ✅ No custom code
* ✅ No custom schema
* ✅ Upgrade‑safe architecture

This is the recommended approach for modern Drupal (11.x).

---

== Key Lesson ==
If a solution requires:
* custom join tables
* extensive hook usage
* complex UI overrides

…it is often a sign that Drupal already offers a better abstraction.

ICT:D Linking Assets to Person - Revision history

Mngr at 19:29, 27 March 2026