wp_delete_term( int $term, string $taxonomy, array|string $args = array() )

从数据库中删除术语。
Removes a term from the database.

目录锚点：#说明#参数#源码#笔记

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说明（Description）

如果术语是其他术语的父项，则子项将更新为该术语的父项。将删除与术语关联的元数据。

参数（Parameters）

源码（Source）

/**
 * Removes a term from the database.
 *
 * If the term is a parent of other terms, then the children will be updated to
 * that term's parent.
 *
 * The `$args` 'default' will only override the terms found, if there is only one
 * term found. Any other and the found terms are used.
 *
 * The $args 'force_default' will force the term supplied as default to be
 * assigned even if the object was not going to be termless
 *
 * @todo Document $args as a hash notation.
 *
 * @since 2.3.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int          $term     Term ID.
 * @param string       $taxonomy Taxonomy Name.
 * @param array|string $args     Optional. Change 'default' term id and override found term ids.
 * @return bool|int|WP_Error Returns false if not term; true if completes delete action.
 */
function wp_delete_term( $term, $taxonomy, $args = array() ) {
	global $wpdb;

	$term = (int) $term;

	if ( ! $ids = term_exists($term, $taxonomy) )
		return false;
	if ( is_wp_error( $ids ) )
		return $ids;

	$tt_id = $ids['term_taxonomy_id'];

	$defaults = array();

	if ( 'category' == $taxonomy ) {
		$defaults['default'] = get_option( 'default_category' );
		if ( $defaults['default'] == $term )
			return 0; // Don't delete the default category
	}

	$args = wp_parse_args($args, $defaults);

	if ( isset( $args['default'] ) ) {
		$default = (int) $args['default'];
		if ( ! term_exists( $default, $taxonomy ) ) {
			unset( $default );
		}
	}

	if ( isset( $args['force_default'] ) ) {
		$force_default = $args['force_default'];
	}

	/**
	 * Fires when deleting a term, before any modifications are made to posts or terms.
	 *
	 * @since 4.1.0
	 *
	 * @param int    $term     Term ID.
	 * @param string $taxonomy Taxonomy Name.
	 */
	do_action( 'pre_delete_term', $term, $taxonomy );

	// Update children to point to new parent
	if ( is_taxonomy_hierarchical($taxonomy) ) {
		$term_obj = get_term($term, $taxonomy);
		if ( is_wp_error( $term_obj ) )
			return $term_obj;
		$parent = $term_obj->parent;

		$edit_ids = $wpdb->get_results( "SELECT term_id, term_taxonomy_id FROM $wpdb->term_taxonomy WHERE `parent` = " . (int)$term_obj->term_id );
		$edit_tt_ids = wp_list_pluck( $edit_ids, 'term_taxonomy_id' );

		/**
		 * Fires immediately before a term to delete's children are reassigned a parent.
		 *
		 * @since 2.9.0
		 *
		 * @param array $edit_tt_ids An array of term taxonomy IDs for the given term.
		 */
		do_action( 'edit_term_taxonomies', $edit_tt_ids );

		$wpdb->update( $wpdb->term_taxonomy, compact( 'parent' ), array( 'parent' => $term_obj->term_id) + compact( 'taxonomy' ) );

		// Clean the cache for all child terms.
		$edit_term_ids = wp_list_pluck( $edit_ids, 'term_id' );
		clean_term_cache( $edit_term_ids, $taxonomy );

		/**
		 * Fires immediately after a term to delete's children are reassigned a parent.
		 *
		 * @since 2.9.0
		 *
		 * @param array $edit_tt_ids An array of term taxonomy IDs for the given term.
		 */
		do_action( 'edited_term_taxonomies', $edit_tt_ids );
	}

	$objects = $wpdb->get_col( $wpdb->prepare( "SELECT object_id FROM $wpdb->term_relationships WHERE term_taxonomy_id = %d", $tt_id ) );

	foreach ( (array) $objects as $object ) {
		$terms = wp_get_object_terms($object, $taxonomy, array('fields' => 'ids', 'orderby' => 'none'));
		if ( 1 == count($terms) && isset($default) ) {
			$terms = array($default);
		} else {
			$terms = array_diff($terms, array($term));
			if (isset($default) && isset($force_default) && $force_default)
				$terms = array_merge($terms, array($default));
		}
		$terms = array_map('intval', $terms);
		wp_set_object_terms($object, $terms, $taxonomy);
	}

	// Clean the relationship caches for all object types using this term.
	$tax_object = get_taxonomy( $taxonomy );
	foreach ( $tax_object->object_type as $object_type )
		clean_object_term_cache( $objects, $object_type );

	// Get the object before deletion so we can pass to actions below
	$deleted_term = get_term( $term, $taxonomy );

	/**
	 * Fires immediately before a term taxonomy ID is deleted.
	 *
	 * @since 2.9.0
	 *
	 * @param int $tt_id Term taxonomy ID.
	 */
	do_action( 'delete_term_taxonomy', $tt_id );
	$wpdb->delete( $wpdb->term_taxonomy, array( 'term_taxonomy_id' => $tt_id ) );

	/**
	 * Fires immediately after a term taxonomy ID is deleted.
	 *
	 * @since 2.9.0
	 *
	 * @param int $tt_id Term taxonomy ID.
	 */
	do_action( 'deleted_term_taxonomy', $tt_id );

	// Delete the term if no taxonomies use it.
	if ( !$wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->term_taxonomy WHERE term_id = %d", $term) ) )
		$wpdb->delete( $wpdb->terms, array( 'term_id' => $term ) );

	clean_term_cache($term, $taxonomy);

	/**
	 * Fires after a term is deleted from the database and the cache is cleaned.
	 *
	 * @since 2.5.0
	 *
	 * @param int     $term         Term ID.
	 * @param int     $tt_id        Term taxonomy ID.
	 * @param string  $taxonomy     Taxonomy slug.
	 * @param mixed   $deleted_term Copy of the already-deleted term, in the form specified
	 *                              by the parent function. WP_Error otherwise.
	 */
	do_action( 'delete_term', $term, $tt_id, $taxonomy, $deleted_term );

	/**
	 * Fires after a term in a specific taxonomy is deleted.
	 *
	 * The dynamic portion of the hook name, `$taxonomy`, refers to the specific
	 * taxonomy the term belonged to.
	 *
	 * @since 2.3.0
	 *
	 * @param int     $term         Term ID.
	 * @param int     $tt_id        Term taxonomy ID.
	 * @param mixed   $deleted_term Copy of the already-deleted term, in the form specified
	 *                              by the parent function. WP_Error otherwise.
	 */
	do_action( "delete_$taxonomy", $term, $tt_id, $deleted_term );

	return true;
}

笔记（Notes）

基本示例