QSqlRelationalTableModel setRelation() unable to select()

[Armin]

Hi,
I'm writing a small application with relations between two tables using SQLLITE. The second Table has a relation to the first one, which works fine with model and tableview, but a query to the second table only works if do not use setrelation(). I mnimzed the code as an example and inserted a fixed query that shoud show one line in the second table (and does that if I comment out the line colorModel->setRelation(color_Other, QSqlRelation("other", "id", "name"));.

What did I wrong with that? Thanks for any hint in advance
Armin

mainwindow.cpp


#include <QtGui>
#include <QtSql>
#include "mainwindow.h"
MainWindow::MainWindow()
{
createOtherDock();
createColorDock();
}
//---------------------------------------------------------------------------
void MainWindow::createOtherDock()
{
QDockWidget *dock = new QDockWidget(tr("Other"), this);

otherModel = new QSqlRelationalTableModel(this);
otherModel->setTable("other");
otherModel->select();

otherView = new QTableView(dock);
otherView->setModel(otherModel);

dock->setWidget(otherView);
addDockWidget(Qt::RightDockWidgetArea, dock);
}
//---------------------------------------------------------------------------
void MainWindow::createColorDock()
{
QDockWidget *dock = new QDockWidget(tr("Color"), this);

colorModel = new QSqlRelationalTableModel(this);
colorModel->setTable("color");
// the following is the line that mixes up the query
colorModel->setRelation(color_Other, QSqlRelation("other", "id", "name"));
colorModel->select();

colorView = new QTableView(dock);
colorView->setModel(colorModel);

dock->setWidget(colorView);
addDockWidget(Qt::RightDockWidgetArea, dock);
}
//---------------------------------------------------------------------------
void MainWindow::filterColorView()
{
colorModel->setFilter("name like 'Bl%'");
colorModel->select();
colorView->horizontalHeader()->setVisible(colorModel->rowCount() > 0);
}



mainwindow.h


#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QtGui>
#include <QtSql>

enum {
other_Id = 0,
other_Name = 1,
};
enum {
color_Id = 0,
color_Name = 1,
color_Other = 2,
};

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
MainWindow();
void filterColorView();
private:
void createOtherDock();
void createColorDock();

QSqlRelationalTableModel *otherModel;
QSqlRelationalTableModel *colorModel;

QTableView *otherView;
QTableView *colorView;

};

#endif



And for convenience if someone wants to compile it, main.cpp:


#include <QApplication>
#include <QtGui>
#include <QtSql>

#include "mainwindow.h"
//---------------------------------------------------------------------------
bool Connect()
{
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("data.dat");
if (!db.open())
{
QMessageBox::warning(0, QObject::tr("Error"), db.lastError().text());
return (false);
}
return (true);
}
//---------------------------------------------------------------------------
void createDataBase()
{
QSqlQuery query;
query.exec("DROP TABLE other");
query.exec("DROP TABLE color");

query.exec("CREATE TABLE other ("
"id INTEGER PRIMARY KEY AUTOINCREMENT, "
"name VARCHAR(10) NOT NULL)");

query.exec("CREATE TABLE color ("
"id INTEGER PRIMARY KEY AUTOINCREMENT, "
"name VARCHAR(40) NOT NULL, "
"otherid INTEGER NOT NULL, "
"FOREIGN KEY (otherid) REFERENCES other)");

query.prepare("INSERT INTO other (id, name) "
"VALUES (:id, :name)");
query.bindValue(":id", 1);
query.bindValue(":name", "A");
query.exec();
query.bindValue(":id", 2);
query.bindValue(":name", "B");
query.exec();

query.prepare("INSERT INTO color (id, name, otherid) "
"VALUES (:id, :name, :otherid)");
query.bindValue(":id", 1);
query.bindValue(":name", "Red");
query.bindValue(":otherid", 1);
query.exec();
query.bindValue(":id", 2);
query.bindValue(":name", "Green");
query.bindValue(":otherid", 2);
query.exec();
query.bindValue(":id", 3);
query.bindValue(":name", "Blue");
query.bindValue(":otherid", 1);
query.exec();
}
//---------------------------------------------------------------------------

int main(int argc, char *argv[])
{
QApplication app(argc, argv);

bool existingData = QFile::exists("data.dat");
if (!Connect())
{
return(1);
}
if (!existingData)
{
createDataBase();
}
MainWindow Window;
Window.show();
Window.filterColorView();
return app.exec();
}

[norobro]

Use "table_name.column_name" in your filter.

[Armin]

Thanks a lot norobro, now it works

[kenez]

Thank you very much norobro, your post was very helpful!