how to save a image file ( say png ) into mysql database?

Hi All

Is there any way to save image/pdf files into the mysql database. I am Qt4/C++ using QMYSQL plugin.
I am able to store and retrieve txt files into the database but not any other type of files.

Please suggest.

create a BLOB field in MySQL database, then convert needed image in base64 using QByteArray::toBase64 and store it in database. to restore image you need to use QByteArray::fromBase64 and then create an image.

i tried the same but it didnt worked.

it works fine for me. what did you try?

i am doing it following way..

say have an image file named: apple.png
i opened the file and read it completely using file.readAll(). and saved it into QString (str).
then i converted this QString(str) into QbyteArray and then called toBase64(). and then tried to save it in database and in same way i tried to read it from database but it didnt worked.

Can you share your sample code for this?

thanx

why are you saving data to QString and then converting it to QByteArray? isn't readAll() alredy returning QByteArray? try to readAll() straight into QByteArray without any QStirings

its not working for me :(

can you show us your code?

Save given QImage directly into QByteArray:

Code:

---

QImage image;
         QByteArray ba;
         QBuffer buffer(&ba);
         buffer.open(QIODevice::WriteOnly);
         image.save(&buffer, "PNG");

---

(Taken from Documentation)

Quote:

---

Originally Posted by spirit

create a BLOB field in MySQL database, then convert needed image in base64 using QByteArray::toBase64 and store it in database. to restore image you need to use QByteArray::fromBase64 and then create an image.

---

Why encode QByteArray to base 64?
BLOB is a binary entry and you can use the QByteArray directely.

SQL stores blob fields internally as 64bit sized byte arrays, so if you don't convert to base 64, you waste 50% of space, though it shouldn't really make anything work/break which previously worked/was broken....
Correct me if I am wrong, I am not very familiar with mySQL

Quote:

---

Originally Posted by soxs060389

SQL stores blob fields internally as 64bit sized byte arrays, so if you don't convert to base 64, you waste 50% of space, though it shouldn't really make anything work/break which previously worked/was broken....
Correct me if I am wrong, I am not very familiar with mySQL

---

Base64 it just a special encoding of binary using 64 char :
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvw xyz0123456789+/"
It's generally use to transfer safely a binary throw network.

http://fr.wikipedia.org/wiki/Base64

If you convert a binary to base64 you increase the binary size by 137%.

But maybe i don't understand something...

I have tried connecting the saving the image to the database, but it fails. i have used the following code for updating the database with the image data:

Code:

---

QScreenShot::QScreenShot(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::QScreenShot)
{
     ui->setupUi(this);
     c=0;
     bool ok=false;
     QDateTime dateTime = QDateTime::currentDateTime();
     QString dateTimeString = dateTime.toString();
 
     QDir().mkdir("D:\\QtImages\\");
     QDir().setCurrent("D:\\QtImages\\");
     QDir().mkdir("ScreenShots");
     QDir().setCurrent("ScreenShots");
     QDir().mkdir(dateTimeString);
 
     QMessageBox::warning(NULL,"DriveList",dateTimeString,QMessageBox::Ok);
 
     QStringList list=QSqlDatabase::drivers();
     QString driveList;
     for(int i=0;i<list.length();i++)
     {
         driveList += list[i];
     }
       //QMessageBox::warning(NULL,"DriveList",driveList,QMessageBox::Ok);
     QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
     db = QSqlDatabase::addDatabase("QODBC");
     db.setDatabaseName("DRIVER={MYSQL ODBC 3.51 Driver};FIL={MYSQL};DBQ=screengrabber");
     db.setHostName("localhost");
     db.setConnectOptions("CLIENT_ODBC");
     //db.setDatabaseName("screengrabber");
     db.setUserName("root");
     db.setPassword("1");
     ok = db.open();
 
     for(;;)
     {
 
            originalPixmap =QPixmap();
            originalPixmap = QPixmap::grabWindow(QApplication::desktop()->winId());
            QString strfname;
            strfname.sprintf("%d",c);
            originalPixmap.save("D:\\image"+strfname+".jpeg","jpeg");
            c++;
            char Data;
            QFile file("D:\\image"+strfname+".jpeg");
            file.open(QIODevice::ReadOnly);
            file.seek(0);
            QByteArray buf;
            buf=file.read(250000);
            QSqlQuery query;
            query.prepare("INSERT INTO log VALUES('grab_date='2011-04-26 15:55:09',ip_address='172.16.0.51',image=:val');");
            query.bindValue ( ":val", buf);
            QString strquery;
            strquery = "INSERT INTO log (grab_date,ip_address,image) VALUES ( '";
            strquery += '2011-04-26 15:55:09';
            strquery += "' , '";
            strquery += '172.16.0.51';
            strquery += "' , ";
            strquery += buf;
            strquery += " );";
 
          //QMessageBox::warning(NULL,"DriveList",strquery,QMessageBox::Ok);
 
            QSqlQuery insertQuery( strquery, db);
            bool done = insertQuery.exec();
 
            QFile newfile("D:\\img.txt");
            newfile.open(QIODevice::WriteOnly);
            newfile.write(buf);
 
            int iSecret, iRandom;
            iSecret = rand() % 20 + 1;
            iRandom=iSecret*60000;
 
            QMutex mutex;
            mutex.lock();
            QWaitCondition waitCondition;
            waitCondition.wait(&mutex, iRandom);
            mutex.unlock();
 
    }
 
}

---