Error: QMYSQL3 not loaded.

[Namrata]

Hi,

I am testing small database program in QT. But while running exe I m getting error 'QMYSQL3' driver not loaded.'. But in QT Designer, using menu 'Project-Dabase connection-', connection is established. Also it is showing 'QMYSQL3' driver.
Here is code:

#include <qapplication.h>
#include <qsqldatabase.h>
#include <qsqlquery.h>
#include "form1.h"
 
 
int main( int argc, char ** argv )
{
    QApplication a( argc, argv );
    QSqlDatabase *db=QSqlDatabase::addDatabase("QMYSQL3");
    db->setDatabaseName("manager");
    db->setUserName("root");
    db->setPassword("");
    db->setHostName("localhost");
    db->open();
        if(!db->open())
    {
	qWarning("Failed to open database.");
    }
    else
    {
	qWarning("Database opened successfully");
    }
    Form1 w;
    w.initValues();
    w.show();
    a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
    return a.exec();
}

#include <qapplication.h>
#include <qsqldatabase.h>
#include <qsqlquery.h>
#include "form1.h"


int main( int argc, char ** argv )
{
    QApplication a( argc, argv );
    QSqlDatabase *db=QSqlDatabase::addDatabase("QMYSQL3");
    db->setDatabaseName("manager");
    db->setUserName("root");
    db->setPassword("");
    db->setHostName("localhost");
    db->open();
        if(!db->open())
    {
	qWarning("Failed to open database.");
    }
    else
    {
	qWarning("Database opened successfully");
    }
    Form1 w;
    w.initValues();
    w.show();
    a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
    return a.exec();
}

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[jacek]

while running exe I m getting error 'QMYSQL3' driver not loaded.'. But in QT Designer, using menu 'Project-Dabase connection-', connection is established. Also it is showing 'QMYSQL3' driver.

Do you have only one copy of Qt installed on your system?

db->open();
if(!db->open())

You open the database twice.

[Namrata]

Thanks for reply. I have tried by commenting that line 'db->open();'.
But error is coming to the line,
'QSqlDatabase *db=QSqlDatabase::addDatabase("QMYSQL3");'

[jacek]

Do you have only one copy of Qt installed on your system?

[Namrata]

Actually I am new in Linux, so please tell how to check only one copy of QT is installed or not

[jacek]

In that case you have probably only one version installed, but you can run ldd on your application and on Qt Designer and check whether paths to libqt-mt in both cases are the same.

What does QSqlDatabase::drivers() return? Do you use qmake?