Question

delete_metadata( string $meta_type,  int $object_id,  string $meta_key,  mixed $meta_value = '',  bool $delete_all = false )

Delete metadata for the specified object.

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description

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参数

$meta_type

(string) (Required) Type of object metadata is for (e.g., comment, post, or user)

$object_id

(int) (Required) ID of the object metadata is for

$meta_key

(string) (Required) Metadata key

$meta_value

(mixed) (Optional) Metadata value. Must be serializable if non-scalar. If specified, only delete metadata entries with this value. Otherwise, delete all entries with the specified meta_key. Pass null,false`, or an empty string to skip this check. (For backward compatibility, it is not possible to pass an empty string to delete those entries with an empty string for a value.)

Default value: ''

$delete_all

(bool) (Optional) If true, delete matching metadata entries for all objects, ignoring the specified object_id. Otherwise, only delete matching metadata entries for the specified object_id.

Default value: false

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返回值

(bool) True on successful delete, false on failure.

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源代码

File: wp-includes/meta.php

function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
	global $wpdb;

	if ( ! $meta_type || ! $meta_key || ! is_numeric( $object_id ) && ! $delete_all ) {
		return false;
	}

	$object_id = absint( $object_id );
	if ( ! $object_id && ! $delete_all ) {
		return false;
	}

	$table = _get_meta_table( $meta_type );
	if ( ! $table ) {
		return false;
	}

	$type_column = sanitize_key($meta_type . '_id');
	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
	// expected_slashed ($meta_key)
	$meta_key = wp_unslash($meta_key);
	$meta_value = wp_unslash($meta_value);

	/**
	 * Filters whether to delete metadata of a specific type.
	 *
	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
	 * object type (comment, post, or user). Returning a non-null value
	 * will effectively short-circuit the function.
	 *
	 * @since 3.1.0
	 *
	 * @param null|bool $delete     Whether to allow metadata deletion of the given type.
	 * @param int       $object_id  Object ID.
	 * @param string    $meta_key   Meta key.
	 * @param mixed     $meta_value Meta value. Must be serializable if non-scalar.
	 * @param bool      $delete_all Whether to delete the matching metadata entries
	 *                              for all objects, ignoring the specified $object_id.
	 *                              Default false.
	 */
	$check = apply_filters( "delete_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $delete_all );
	if ( null !== $check )
		return (bool) $check;

	$_meta_value = $meta_value;
	$meta_value = maybe_serialize( $meta_value );

	$query = $wpdb->prepare( "SELECT $id_column FROM $table WHERE meta_key = %s", $meta_key );

	if ( !$delete_all )
		$query .= $wpdb->prepare(" AND $type_column = %d", $object_id );

	if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value )
		$query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );

	$meta_ids = $wpdb->get_col( $query );
	if ( !count( $meta_ids ) )
		return false;

	if ( $delete_all ) {
		$value_clause = '';
		if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value ) {
			$value_clause = $wpdb->prepare( " AND meta_value = %s", $meta_value );
		}

		$object_ids = $wpdb->get_col( $wpdb->prepare( "SELECT $type_column FROM $table WHERE meta_key = %s $value_clause", $meta_key ) );
	}

	/**
	 * Fires immediately before deleting metadata of a specific type.
	 *
	 * The dynamic portion of the hook, `$meta_type`, refers to the meta
	 * object type (comment, post, or user).
	 *
	 * @since 3.1.0
	 *
	 * @param array  $meta_ids   An array of metadata entry IDs to delete.
	 * @param int    $object_id  Object ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 */
	do_action( "delete_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );

	// Old-style action.
	if ( 'post' == $meta_type ) {
		/**
		 * Fires immediately before deleting metadata for a post.
		 *
		 * @since 2.9.0
		 *
		 * @param array $meta_ids An array of post metadata entry IDs to delete.
		 */
		do_action( 'delete_postmeta', $meta_ids );
	}

	$query = "DELETE FROM $table WHERE $id_column IN( " . implode( ',', $meta_ids ) . " )";

	$count = $wpdb->query($query);

	if ( !$count )
		return false;

	if ( $delete_all ) {
		foreach ( (array) $object_ids as $o_id ) {
			wp_cache_delete($o_id, $meta_type . '_meta');
		}
	} else {
		wp_cache_delete($object_id, $meta_type . '_meta');
	}

	/**
	 * Fires immediately after deleting metadata of a specific type.
	 *
	 * The dynamic portion of the hook name, `$meta_type`, refers to the meta
	 * object type (comment, post, or user).
	 *
	 * @since 2.9.0
	 *
	 * @param array  $meta_ids   An array of deleted metadata entry IDs.
	 * @param int    $object_id  Object ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 */
	do_action( "deleted_{$meta_type}_meta", $meta_ids, $object_id, $meta_key, $_meta_value );

	// Old-style action.
	if ( 'post' == $meta_type ) {
		/**
		 * Fires immediately after deleting metadata for a post.
		 *
		 * @since 2.9.0
		 *
		 * @param array $meta_ids An array of deleted post metadata entry IDs.
		 */
		do_action( 'deleted_postmeta', $meta_ids );
	}

	return true;
}

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更新日志

Version	description
2.9.0	Introduced.

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相关函数

Uses

• wp-includes/cache.php: wp_cache_delete()
• wp-includes/formatting.php: wp_unslash()
• wp-includes/formatting.php: sanitize_key()
• wp-includes/functions.php: absint()
• wp-includes/functions.php: maybe_serialize()
• wp-includes/plugin.php: apply_filters()
• wp-includes/plugin.php: do_action()
• wp-includes/wp-db.php: wpdb::get_col()
• wp-includes/wp-db.php: wpdb::query()
• wp-includes/wp-db.php: wpdb::prepare()
• wp-includes/meta.php: _get_meta_table()
• wp-includes/meta.php: delete_{$meta_type}_metadata
• wp-includes/meta.php: delete_{$meta_type}_meta
• wp-includes/meta.php: delete_postmeta
• wp-includes/meta.php: deleted_{$meta_type}_meta
• wp-includes/meta.php: deleted_postmeta
Show 11 more uses Hide more uses

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Used By

• wp-includes/rest-api/fields/class-wp-rest-meta-fields.php: WP_REST_Meta_Fields::delete_meta_value()
• wp-includes/rest-api/fields/class-wp-rest-meta-fields.php: WP_REST_Meta_Fields::update_multi_meta_value()
• wp-includes/taxonomy.php: delete_term_meta()
• wp-includes/class-wp-user-meta-session-tokens.php: WP_User_Meta_Session_Tokens::drop_sessions()
• wp-includes/user.php: delete_user_meta()
• wp-includes/post.php: wp_delete_attachment()
• wp-includes/post.php: delete_post_meta()
• wp-includes/post.php: delete_post_meta_by_key()
• wp-includes/ms-functions.php: install_blog()
• wp-includes/comment.php: delete_comment_meta()
Show 5 more used by Hide more used by

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User Contributed Notes