private function appendQueryParameter($parameter)
    {
        preg_match($this->pattern, $parameter, $matches);

        if (empty($matches)) {
            return;
        }

        $operator = $matches[0];

        list($key, $value) = explode($operator, $parameter);

        if (strlen($value) == 0) {
            return;
        }

        if (( ! $this->isPredefinedParameter($key)) && $this->isLikeQuery($value)) {
            if ($operator == '=') {
                $operator = 'like';
            }
            if ($operator == '!=') {
                $operator = 'not like';
            }

            $value = str_replace('*', '%', $value);
        }

        $this->queryParameters[] = [
            'key' => $key,
            'operator' => $operator,
            'value' => $value
        ];
    }