>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3263331. --> Reported by: [anybody](https://www.drupal.org/user/291091) >>> <p><em>This is not something the maintainer has to do, just wanted to leave the idea, as I guess field tools would be the perfect place for this!<br> The maintainer should decide if and how (submodule or direct) this should be done. Others running into the same situation, please help with implementation!</em></p> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>Having a Drupal project growing over years may leave orphaned field tables and / or field values in the database.</p> <p>For example, field tables typically reference a parent entity of a certain bundle. If that entity or bundle was deleted (even if only in the referenced revision) but the field values were not, this messes up the database.</p> <p>The same may happen if Drupal fails to clean up removed field database tables and these tables are left in the database while the field has been removed long ago.<br> I saw both cases quite often in the past due to different reasons. For Drupal 8 I didn't find a related module yet.</p> <h4 id="summary-steps-reproduce">Steps to reproduce</h4> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <p><a href="https://www.drupal.org/project/entity_reference_revisions">https://www.drupal.org/project/entity_reference_revisions</a> added a helpful page to remove orphaned composite entities. While it doesn't list the entities which will be deleted (which I think would be a useful bonus to let the administrator review it), it batch deletes these orphaned references based on entity types and does its job very well.</p> <p>Same should be done for fields, but with a review step, listing the field values and tables (separate selection) that will be removed in a checklist. It should also be possible to select the host entity types to run the checks for, as fields are always assigned to an entity type.</p> <p>I guess most of the admin page and batch boilerplate code can be reused from entity_reference_revisions while the different strategies to detect these orphans have to be implemented individually.</p> <p><strong>Cases to consider:</strong></p> <ul> <li>Orphaned field tables</li> <li>Orphaned field values referencing a non-existing bundle / entitiy (id, revision, language)</li> <li>...?</li> </ul> <h3 id="summary-remaining-tasks">Remaining tasks</h3> <ol> <li>Discuss</li> <li>Plan</li> <li>Implement &amp; write tests</li> <li>Test</li> <li>Release</li> </ol> <h3 id="summary-ui-changes">User interface changes</h3> <h3 id="summary-api-changes">API changes</h3> <h3 id="summary-data-model-changes">Data model changes</h3> <h3>References / related issues</h3> <p><span class="drupalorg-gitlab-issue-link project-issue-status-info project-issue-status-3"><a href="https://www.drupal.org/project/drupal/issues/838022" title="Status: Closed (duplicate)">#838022: Deleting a content type leaves orphaned fields</a></span><br> <a href="https://www.drupal.org/forum/support/post-installation/2012-05-23/erase-unused-fields">https://www.drupal.org/forum/support/post-installation/2012-05-23/erase-unused-fields</a><br> <a href="https://drupal.stackexchange.com/questions/38328/clean-deleted-field-from-database">https://drupal.stackexchange.com/questions/38328/clean-deleted-field-from-database</a><br> <a href="https://drupal.stackexchange.com/questions/230156/how-to-make-drupal-8-forget-an-old-deleted-field/230199">https://drupal.stackexchange.com/questions/230156/how-to-make-drupal-8-forget-an-old-deleted-field/230199</a></p>