Using QSqlRelationalTableModel : QSqlRelationalTableModel « Qt « C++






Using QSqlRelationalTableModel

  
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#ifndef CONNECTION_H
#define CONNECTION_H

#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>

/*
    This file defines a helper function to open a connection to an
    in-memory SQLITE database and to create a test table.

    If you want to use another database, simply modify the code
    below. All the examples in this directory use this function to
    connect to a database.
*/

static bool createConnection()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(":memory:");
    if (!db.open()) {
        QMessageBox::critical(0, qApp->tr("Cannot open database"),
            qApp->tr("Unable to establish a database connection.\n"
                     "This example needs SQLite support. Please read "
                     "the Qt SQL driver documentation for information how "
                     "to build it.\n\n"
                     "Click Cancel to exit."), QMessageBox::Cancel);
        return false;
    }

    QSqlQuery query;
    query.exec("create table person (id int primary key, "
               "firstname varchar(20), lastname varchar(20))");
    query.exec("insert into person values(101, 'Danny', 'Young')");
    query.exec("insert into person values(102, 'Christine', 'Holand')");
    query.exec("insert into person values(103, 'Lars', 'Gordon')");
    query.exec("insert into person values(104, 'Roberto', 'Robitaille')");
    query.exec("insert into person values(105, 'Maria', 'Papadopoulos')");

    query.exec("create table offices (id int primary key,"
                                             "imagefile int,"
                                             "location varchar(20),"
                                             "country varchar(20),"
                                             "description varchar(100))");
    query.exec("insert into offices "
               "values(0, 0, 'Oslo', 'Norway',"
               "'Oslo is home to more than 500 000 citizens and has a "
               "lot to offer.It has been called \"The city with the big "
               "heart\" and this is a nickname we are happy to live up to.')");
    query.exec("insert into offices "
               "values(1, 1, 'Brisbane', 'Australia',"
               "'Brisbane is the capital of Queensland, the Sunshine State, "
               "where it is beautiful one day, perfect the next.  "
               "Brisbane is Australia''s 3rd largest city, being home "
               "to almost 2 million people.')");
    query.exec("insert into offices "
               "values(2, 2, 'Redwood City', 'US',"
               "'You find Redwood City in the heart of the Bay Area "
               "just north of Silicon Valley. The largest nearby city is "
               "San Jose which is the third largest city in California "
               "and the 10th largest in the US.')");
    query.exec("insert into offices "
               "values(3, 3, 'Berlin', 'Germany',"
               "'Berlin, the capital of Germany is dynamic, cosmopolitan "
               "and creative, allowing for every kind of lifestyle. "
               "East meets West in the metropolis at the heart of a "
               "changing Europe.')");
    query.exec("insert into offices "
               "values(4, 4, 'Munich', 'Germany',"
               "'Several technology companies are represented in Munich, "
               "and the city is often called the \"Bavarian Silicon Valley\". "
               "The exciting city is also filled with culture, "
               "art and music. ')");
    query.exec("insert into offices "
               "values(5, 5, 'Beijing', 'China',"
               "'Beijing as a capital city has more than 3000 years of "
               "history. Today the city counts 12 million citizens, and "
               "is the political, economic and cultural centre of China.')");

    query.exec("create table images (locationid int, file varchar(20))");
    query.exec("insert into images values(0, 'images/oslo.png')");
    query.exec("insert into images values(1, 'images/brisbane.png')");
    query.exec("insert into images values(2, 'images/redwood.png')");
    query.exec("insert into images values(3, 'images/berlin.png')");
    query.exec("insert into images values(4, 'images/munich.png')");
    query.exec("insert into images values(5, 'images/beijing.png')");



    return true;
}


#endif








#include <QtGui>
#include <QtSql>

#include "../connection.h"

void initializeModel(QSqlRelationalTableModel *model)
{

    model->setTable("employee");


    model->setEditStrategy(QSqlTableModel::OnManualSubmit);

    model->setRelation(2, QSqlRelation("city", "id", "name"));
 
    model->setRelation(3, QSqlRelation("country", "id", "name"));
  


    model->setHeaderData(0, Qt::Horizontal, QObject::tr("ID"));
    model->setHeaderData(1, Qt::Horizontal, QObject::tr("Name"));
    model->setHeaderData(2, Qt::Horizontal, QObject::tr("City"));
    model->setHeaderData(3, Qt::Horizontal, QObject::tr("Country"));


    model->select();
}

QTableView *createView(const QString &title, QSqlTableModel *model)
{

    QTableView *view = new QTableView;
    view->setModel(model);
    view->setItemDelegate(new QSqlRelationalDelegate(view));

    view->setWindowTitle(title);
    return view;
}

void createRelationalTables()
{
    QSqlQuery query;
    query.exec("create table employee(id int primary key, name varchar(20), city int, country int)");
    query.exec("insert into employee values(1, 'Espen', 5000, 47)");
    query.exec("insert into employee values(2, 'Harald', 80000, 49)");
    query.exec("insert into employee values(3, 'Sam', 100, 1)");

    query.exec("create table city(id int, name varchar(20))");
    query.exec("insert into city values(100, 'San Jose')");
    query.exec("insert into city values(5000, 'Oslo')");
    query.exec("insert into city values(80000, 'Munich')");

    query.exec("create table country(id int, name varchar(20))");
    query.exec("insert into country values(1, 'USA')");
    query.exec("insert into country values(47, 'Norway')");
    query.exec("insert into country values(49, 'Germany')");
}

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    if (!createConnection())
        return 1;
    createRelationalTables();

    QSqlRelationalTableModel model;

    initializeModel(&model);

    QTableView *view = createView(QObject::tr("Relational Table Model"), &model);
    view->show();

    return app.exec();
}

   
    
  








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