Displat query results in a table

[mi08037]

Greetings,

I finally managed to get the MySQL driver to work and now I'm trying to present my sql query in a relational table with no success, i tried to figure out the example given by qt and program something similar.

What i managed to do is to print query results in command line but I cant display the results in a table on button click i think that i have segmentation fault but i cant figure out where because debugger shows assembler code.

Here is the code:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QtSql>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
 
private slots:
    void on_pushButton_2_clicked();
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtSql>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

private slots:
    void on_pushButton_2_clicked();
};

#endif // MAINWINDOW_H

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#include <QtGui/QApplication>
#include "mainwindow.h"
#include <QtSql>
 
int main(int argc, char *argv[])
{
    int testUpload;
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
 
    return a.exec();
}

#include <QtGui/QApplication>
#include "mainwindow.h"
#include <QtSql>

int main(int argc, char *argv[])
{
    int testUpload;
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

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#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSql>
#include <string>
#include <iostream>
 
using namespace std;
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_2_clicked()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
        db.setHostName("localhost");
        db.setDatabaseName("mysql");
        db.setUserName("root");
        db.setPassword("");
        if (!db.open())
            cout << "Fail!" << endl;
        else
            cout << "Success!" << endl;
 
        QSqlQuery query("SELECT * FROM help_keyword");
        QSqlRecord rec = query.record();
        query.exec();
 
        QSqlRelationalTableModel *model;
        model->setTable("Kljucne reci");
        for(int j = 0; j < rec.count();j++) {
            string atr = rec.field(j).name().toStdString();
            // Here is supposed to be field name but i dont know how to convert string or QString to const char * so i placed arbitary text just test it
            model->setHeaderData(j, Qt::Horizontal, "lala");
        }
        model->select();
        QTableView *tb = new QTableView;
        tb->setModel(model);
        //tb->setItemDelegate(new QSqlRelationalDelegate(tb));
        tb->setWindowTitle("Kljucne reci!");
     /*
      * Command line output (works)
        while(query.next()) {
            cout << endl;
            for(int i = 0; i < rec.count(); i++) {
                QString str = query.value(i).toString();
                cout << str.toStdString() << " ";
            }
        }
        cout << endl;
    */
        tb->show();
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSql>
#include <string>
#include <iostream>

using namespace std;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

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

void MainWindow::on_pushButton_2_clicked()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
        db.setHostName("localhost");
        db.setDatabaseName("mysql");
        db.setUserName("root");
        db.setPassword("");
        if (!db.open())
            cout << "Fail!" << endl;
        else
            cout << "Success!" << endl;

        QSqlQuery query("SELECT * FROM help_keyword");
        QSqlRecord rec = query.record();
        query.exec();

        QSqlRelationalTableModel *model;
        model->setTable("Kljucne reci");
        for(int j = 0; j < rec.count();j++) {
            string atr = rec.field(j).name().toStdString();
            // Here is supposed to be field name but i dont know how to convert string or QString to const char * so i placed arbitary text just test it
            model->setHeaderData(j, Qt::Horizontal, "lala");
        }
        model->select();
        QTableView *tb = new QTableView;
        tb->setModel(model);
        //tb->setItemDelegate(new QSqlRelationalDelegate(tb));
        tb->setWindowTitle("Kljucne reci!");
     /*
      * Command line output (works)
        while(query.next()) {
            cout << endl;
            for(int i = 0; i < rec.count(); i++) {
                QString str = query.value(i).toString();
                cout << str.toStdString() << " ";
            }
        }
        cout << endl;
    */
        tb->show();
}

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[Rhayader]

*model is not initialized.
line 37 should be

QSqlRelationalTableModel *model=new QSqlRelationalTableModel(this);

QSqlRelationalTableModel *model=new QSqlRelationalTableModel(this);

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[mi08037]

I figured out that using relationalmodel is not good choice since i'll have an arbitary query to display so i switched to other technique

I get the corretly sized empty table but no query result values are inserted

Here is the code:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSql>
#include <string>
#include <iostream>
 
using namespace std;
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_pushButton_2_clicked()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
        db.setHostName("localhost");
        db.setDatabaseName("mysql");
        db.setUserName("root");
        db.setPassword("");
        if (!db.open())
            cout << "Fail!" << endl;
        else
            cout << "Success!" << endl;
 
        QSqlQuery query("SELECT * FROM db");
        QSqlRecord rec = query.record();
        query.exec();
 
        int k=0;
        while(query.next()) {
            k++;
        }
 
        ui->tableWidget->setRowCount(k);
        ui->tableWidget->setColumnCount(rec.count());
        int m=0;
        while(query.next()) {
            for(int i = 0; i < rec.count(); i++) {
                 QString str = query.value(i).toString();
                 QTableWidgetItem *item = new QTableWidgetItem();
                 item->setData(Qt::UserRole,str);
                 ui->tableWidget->setItem(m,i,item);
            }
            m++;
        }
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtSql>
#include <string>
#include <iostream>

using namespace std;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

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

void MainWindow::on_pushButton_2_clicked()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
        db.setHostName("localhost");
        db.setDatabaseName("mysql");
        db.setUserName("root");
        db.setPassword("");
        if (!db.open())
            cout << "Fail!" << endl;
        else
            cout << "Success!" << endl;

        QSqlQuery query("SELECT * FROM db");
        QSqlRecord rec = query.record();
        query.exec();

        int k=0;
        while(query.next()) {
            k++;
        }

        ui->tableWidget->setRowCount(k);
        ui->tableWidget->setColumnCount(rec.count());
        int m=0;
        while(query.next()) {
            for(int i = 0; i < rec.count(); i++) {
                 QString str = query.value(i).toString();
                 QTableWidgetItem *item = new QTableWidgetItem();
                 item->setData(Qt::UserRole,str);
                 ui->tableWidget->setItem(m,i,item);
            }
            m++;
        }
}

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[Rhayader]

line 49. you should not set the data as UserRole

[mi08037]

Ok, If that is the only problem and if that method is correct what am i supposed to set it to?

Regards,
Vlad

[Rhayader]

Here you can read about the roles http://doc.qt.nokia.com/latest/qt.ht...mDataRole-enum
The easiest way is to use item->setText(str) or pass str as argument in item's constructor. Since you are using QTableWidget you should familiarise yourself with QTableWidget and QTableWidgetItem