WPDB Update

gistfile1.php

<?php
// table, $data, $where, $format, $where_format
$wpdb->update(
				$wpdb->postmeta,
				array(
						'meta_value'	=>	'false'
						),
				array(
						'post_id'	=> 5,
						'meta_key'	=> '_custom_meta_key',
						),
				array(
						'%s'
						),
				array(
						'%d',
						'%s'
						)
				);
?>