QSqlQuery::prepare: database not open

Lasith

I am writing a program to access an oracle database( driver loaded successfully)! But when I run the program and click the button I get the above stated error!
Following is my header file

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtSql>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public : QSqlDatabase mydb;

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void getInput1();
void getInput2();
void getInput3();
void getInput4();
void getInput5();
private slots:
void on_pushButton_clicked();

private:
Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

Following is my cpp file

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QtSql"
#include "QString"

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
mydb=QSqlDatabase::addDatabase("QOCI");
connect(ui->uname,SIGNAL(returnPressed()),this,SLOT(getInput1()));
connect(ui->pword,SIGNAL(returnPressed()),this,SLOT(getInput2()));
connect(ui->ip,SIGNAL(returnPressed()),this,SLOT(getInput3()));
connect(ui->port,SIGNAL(returnPressed()),this,SLOT(getInput4()));
connect(ui->sname,SIGNAL(returnPressed()),this,SLOT(getInput5()));
mydb.open();
}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::getInput1(){
QString a=ui->uname->text();
mydb.setUserName(a);
}
void MainWindow::getInput2(){
QString b=ui->pword->text();
mydb.setPassword(b);
}
void MainWindow::getInput3(){
QString c=ui->ip->text();
mydb.setHostName(c);
}
void MainWindow::getInput4(){
QString d=ui->port->text();
int e = d.toInt();
mydb.setPort(e);
}
void MainWindow::getInput5(){
QString e=ui->sname->text();
mydb.setDatabaseName(e);
}

void MainWindow::on_pushButton_clicked()
{
mydb.open();

QSqlQueryModel *modal = new QSqlQueryModel();

QSqlQuery* qry=new QSqlQuery(mydb);


qry->prepare("select NAME FROM TEST1");
   qry->exec();
   modal->setQuery(*qry);
   ui->tableView->setModel(modal);

}

dheerendra

since it is oracledb, it may be asking for u to give username, password,hostname etc inputs. please check it.

Lasith

@dheerendra I've already given them using signals and slots

dheerendra

r u able to connect to db outside qt program ?

Lasith

@dheerendra Yes!

mostefa

@Lasith said in QSqlQuery::prepare: database not open:

mydb.open();

Hi i think that the reason of your problem is that you are opening database juste after SIGNAL/SLOT connections even if signals are not triggered,

Just before

mydb.open();

you can try to add

qDebug() << mydb.username() << mydb.hostname();

Value of username will be empty and value of hostname will be empty too,

The Qt doc says:

bool QSqlDatabase::open ()

Opens the database connection using the current connection values. Returns true on success; otherwise returns false.

Or even you can do this after open():

if(mydb.open())
{
   qDebug() << "database correctly opened";
}
else
{
 qDebug() << mydb.username << mydb.hostname ; //these values will be null
}

I hope this can help you!

Lasith

@mostefa Thanx mate