public function init()
{
if (is_string($this->db)) {
$this->db = Yii::$app->get($this->db);
}
if (!$this->db instanceof Connection) {
throw new InvalidConfigException("DbSession::db must be either a DB connection instance or the application component ID of a DB connection.");
}
if (!$this->sessionTable) {
$this->sessionTable = $this->db->tablePrefix . 'session';
}
parent::init();
}