private function hasMinimumCredentials(): bool {
        if (!isset($this->credentials["servername"])) {
            return false;
        }
        if (!isset($this->credentials["username"])) {
            return false;
        }
        if (!isset($this->credentials["password"])) {
            return false;
        }
        if (!isset($this->credentials["dbname"])) {
            return false;
        }
        return true;
    }