QSqlQuery::isValid returns false

[mismael85]

that is the code i use

#include "shamelareader.h"
 
shamelaReader::shamelaReader(QWidget *parent)
	: QMainWindow(parent)
{
	mainText = new QTextEdit(this);
	setCentralWidget(mainText);
 
	db= QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb)};FIL={MS Access};DBQ=c:\\book.mdb");
	db.open();
 
 
	createActions();
    createToolBar();
 
    query = new QSqlQuery();
    query->exec("SELECT name FROM employee");
	query->next();
	mainText->setText(query->value(0).toString());
 
}
void shamelaReader::createActions()
{
	nextAct = new QAction(tr("&Next"),this);
	connect(nextAct, SIGNAL(triggered()), this, SLOT(next()));
 
	prevAct = new QAction(tr("&previous"),this);
	connect(prevAct, SIGNAL(triggered()), this, SLOT(prev()));
 
	firstAct = new QAction(tr("first"), this);
	connect(firstAct, SIGNAL(triggered()), this, SLOT(first()));
 
	lastAct = new QAction(tr("last"), this);
	connect(lastAct, SIGNAL(triggered()), this, SLOT(last()));
 
 
}
 
void shamelaReader::createToolBar()
{
  toolBar = addToolBar(tr("Navigation"));
  toolBar->addAction(firstAct);
  toolBar->addAction(nextAct);
  toolBar->addAction(prevAct);
  toolBar->addAction(lastAct);
}
 
void shamelaReader::next()
{
 query->next();
 mainText->setText(query->value(0).toString());
}
 
void shamelaReader::prev()
{
	query->previous();
    mainText->setText(query->value(0).toString());
}
 
void shamelaReader::first()
{
    query->first();
    mainText->setText(query->value(0).toString());
}
 
void shamelaReader::last()
{
 
	query->last();
	if(query->isActive())
        QMessageBox::warning(this, "title", "Active true");
 
	if(query->isValid())
		QMessageBox::warning(this, "title", "true");
 
    mainText->setText(query->value(0).toString());
}

#include "shamelareader.h"

shamelaReader::shamelaReader(QWidget *parent)
	: QMainWindow(parent)
{
	mainText = new QTextEdit(this);
	setCentralWidget(mainText);
  
	db= QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb)};FIL={MS Access};DBQ=c:\\book.mdb");
	db.open();
		
    
	createActions();
    createToolBar();

    query = new QSqlQuery();
    query->exec("SELECT name FROM employee");
	query->next();
	mainText->setText(query->value(0).toString());
	
}
void shamelaReader::createActions()
{
	nextAct = new QAction(tr("&Next"),this);
	connect(nextAct, SIGNAL(triggered()), this, SLOT(next()));

	prevAct = new QAction(tr("&previous"),this);
	connect(prevAct, SIGNAL(triggered()), this, SLOT(prev()));

	firstAct = new QAction(tr("first"), this);
	connect(firstAct, SIGNAL(triggered()), this, SLOT(first()));

	lastAct = new QAction(tr("last"), this);
	connect(lastAct, SIGNAL(triggered()), this, SLOT(last()));


}

void shamelaReader::createToolBar()
{
  toolBar = addToolBar(tr("Navigation"));
  toolBar->addAction(firstAct);
  toolBar->addAction(nextAct);
  toolBar->addAction(prevAct);
  toolBar->addAction(lastAct);
}

void shamelaReader::next()
{
 query->next();
 mainText->setText(query->value(0).toString());
}

void shamelaReader::prev()
{
	query->previous();
    mainText->setText(query->value(0).toString());
}

void shamelaReader::first()
{
    query->first();
    mainText->setText(query->value(0).toString());
}

void shamelaReader::last()
{
	
	query->last();
	if(query->isActive())
        QMessageBox::warning(this, "title", "Active true");

	if(query->isValid())
		QMessageBox::warning(this, "title", "true");

    mainText->setText(query->value(0).toString());
}

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