global $wpdb;
	$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'categories' );
	$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'link2cat' );
	$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'post2cat' );
}

/**
 * Upgrade old slugs made in version 2.2.
 *
 * @ignore
 * @since 2.2.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 */
function upgrade_old_slugs() {
	// Upgrade people who were using the Redirect Old Slugs plugin.
	global $wpdb;
	$wpdb->query( "UPDATE $wpdb->postmeta SET meta_key = '_wp_old_slug' WHERE meta_key = 'old_slug'" );
}

/**
 * Execute changes made in WordPress 2.5.0.
 *
 * @ignore
 * @since 2.5.0
 *
 * @global int $wp_current_db_version The old (current) database version.
 */
function upgrade_250() {
	global $wp_current_db_version;

	if ( $wp_current_db_version < 6689 ) {
		populate_roles_250();
	}

}

/**
 * Execute changes made in WordPress 2.5.2.
 *