How to getblob data from SQL and display in gridview using pixmap in C++ 98?

See more:

C++

SQL

QT

C++98

BMP

I am new in C++ .I am trying to load blob image which is stored in .bin file from sql Database. That .bin file store blob image in form of string like BM6 ect(each .bin have 3 to 4 char).

Here is code(working) that save the blob image(.bmp) in db

QPixmap p;
            p.load(filename);
    
      
            string a = "/root/QtApplication_1/file";        
            string b = boost::lexical_cast<std::string>(counter);
            string c = ".bmp";
            
            p.save(("/root/QtApplication_1/file"+boost::lexical_cast<std::string>(counter)+".bmp").c_str(),"BMP");
            std::string d = a + b + c ;
            
            
            std::ifstream blob_file;
            blob_file.open(d.c_str(), std::ios_base::binary | std::ifstream::in);
            
        driver = get_driver_instance();
        con = driver->connect("localhost","","");
        con->setSchema("BitmapImagesSchema");
    
        
        prep_stmt = con->prepareStatement("Insert into bitmapImagesTable(`ID`,`ImageDir`,`ImagesBitMap`) values(?,?,?)");
        prep_stmt->setInt(1,counter);
     // 
        prep_stmt->setString(2,d.c_str());
      //  byte *p = "" ;
        prep_stmt->setBlob(3,&blob_file);
            
        prep_stmt->executeQuery();
       
        delete prep_stmt;

What I have tried:

Here is my code(not working) that i am trying to get blob image from db and dispaly in QgraphicsView using pixmap

driver = get_driver_instance();
    con = driver->connect("localhost","","");
    con->setSchema("BitmapImagesSchema");
    stmt = con-> createStatement();
    
    std::istream *blobData;
    res = stmt->executeQuery("select `ImagesBitMap` from bitmapImagesTable where `ID`='"+boost::lexical_cast<std::string>(counter)+"'order by `ID` DESC");
    while(res->last()){
        blobData = res->getBlob("ImagesBitMap");
        break;
    }
    
    std::istreambuf_iterator<char> isb = std::istreambuf_iterator<char>(*blobData);
    std::string blobString  = std::string(isb,std::istreambuf_iterator<char>());
    const char * image = blobString.c_str();
    blobData->seekg(0,ios::end);
    size_t imagesize = blobData->tellg();
    
    cout<<"aaa="<<image<<"\n";
    QPixmap p;
    p.load(image);
    if(!widget.graphicsView_2->scene()){
    QGraphicsScene  *scene = new QGraphicsScene(this);
    widget.graphicsView_2->setScene(scene);
    }
            
    widget.graphicsView_2->scene()->addPixmap(p);
    
   
   
    delete res;
    delete stmt;
    delete con;

Graphics view that is using pixmap is not display blob image on button click that execute above code.
The code for reading blob image i have taken from this
link

Here is blob data base that is .bin file
image


Here is the out put of the image varibale

cout<<"aaa="<<image<<"\n";

image


How to display blob image by using above code?