Plugin Uninstall: How to Delete Terms & Taxonomies from WordPress Database

Travis Smith

10 years ago

Many developers do not consider what they should do when a person deactivates a plugin (like flush_rewrite_rules()), much less what to do with the data the plugin created, much of which is useless. In my opinion, this is partly because creating an extra uninstall.php file is a bit problematic to test over and over.

So, in this snippet, here is how you can delete ALL the terms and the associated taxonomy when a plugin is deleted by a user. First create a file called uninstall.php which appears at the root of the plugin. Then add this code:

  
          <?php
        
          /** Delete All the Taxonomies */
        
          foreach ( array( 'my_first_custom_tax', 'my_second_custom_tax', 'my_third_custom_tax', ) as $taxonomy ) {
        
          	// Prepare & excecute SQL, Delete Terms
        
          	$wpdb->get_results( $wpdb->prepare( "DELETE t.*, tt.* FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('%s')", $taxonomy ) );
        
          	// Delete Taxonomy
        
          	$wpdb->delete( $wpdb->term_taxonomy, array( 'taxonomy' => $taxonomy ), array( '%s' ) );
        
          }

view raw uninstall-terms-taxonomy-1.php hosted with ❤ by GitHub

Sometimes, however, you may need to do something else between the code. For example, you may have custom term meta within the options table that would need to be deleted as well.

  
          <?php
        
          /** Delete All the Taxonomies */
        
          foreach ( array( 'my_first_custom_tax', 'my_second_custom_tax', 'my_third_custom_tax', ) as $taxonomy ) {
        
          	// Prepare & excecute SQL
        
          	$terms = $wpdb->get_results( $wpdb->prepare( "SELECT t.*, tt.* FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('%s') ORDER BY t.name ASC", $taxonomy ) );
        
                  // Delete Terms
        
          	if ( $terms ) {
        
          		foreach ( $terms as $term ) {
        
          			$wpdb->delete( $wpdb->term_taxonomy, array( 'term_taxonomy_id' => $term->term_taxonomy_id ) );
        
          			$wpdb->delete( $wpdb->terms, array( 'term_id' => $term->term_id ) );
        
          			delete_option( 'prefix_' . $taxonomy->slug . '_option_name' );
        
          		}
        
          	}
        
          	// Delete Taxonomy
        
          	$wpdb->delete( $wpdb->term_taxonomy, array( 'taxonomy' => $taxonomy ), array( '%s' ) );
        
          }

view raw uninstall-terms-taxonomy-2.php hosted with ❤ by GitHub

	<?php

	/** Delete All the Taxonomies */
	foreach ( array( 'my_first_custom_tax', 'my_second_custom_tax', 'my_third_custom_tax', ) as $taxonomy ) {
	// Prepare & excecute SQL, Delete Terms
	$wpdb->get_results( $wpdb->prepare( "DELETE t., tt. FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('%s')", $taxonomy ) );

	// Delete Taxonomy
	$wpdb->delete( $wpdb->term_taxonomy, array( 'taxonomy' => $taxonomy ), array( '%s' ) );
	}