public function createIndex($name, $table, $columns, $unique=false)
	{
		echo "    > create".($unique ? ' unique':'')." index $name on $table (".(is_array($columns) ? implode(',', $columns) : $columns).") ...";
		$time=microtime(true);
		$this->getDbConnection()->createCommand()->createIndex($name, $table, $columns, $unique);
		echo " done (time: ".sprintf('%.3f', microtime(true)-$time)."s)\n";
	}