OpenCV print descriptor value

edit

I'm writing a C++ program that should store in a MySQL DB the image descriptors value. I'm using ORB and as far as I know, I should have an 128 bit long value. When I run the following code

for (int p = 0; p < 500; p++){

        if (p == 499){

            cerr << "linia i coloana 0" << descriptors_2.row(p).col(0) << endl;
            cerr << "linia i coloana 0" << descriptors_2.col(0).row(p) << endl;
            cerr << (float)descriptors_2.at<float>(p, 0);

            float test = descriptors_2.at<float>(p, 0);
            cerr << "p,0" << test << endl;

        }

    }

I get the result shown in the picture.

I'm wondering if the hexa value is the one that I should store or is there something that I am doing wrong. Please help me find the problem.