Question

/****************************************************************************
** $Id$
**
** Copyright (C) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#include "main.h"
#include <qdatatable.h>

InvoiceItemCursor::InvoiceItemCursor() :
    QSqlCursor( "invoiceitem" )
{
    QSqlFieldInfo productName( "productname", QVariant::String );
    append( productName );
    setCalculated( productName.name(), TRUE );

    QSqlFieldInfo productPrice( "price", QVariant::Double );
    append( productPrice );
    setCalculated( productPrice.name(), TRUE );

    QSqlFieldInfo productCost( "cost", QVariant::Double );
    append( productCost );
    setCalculated( productCost.name(), TRUE );
}


QVariant InvoiceItemCursor::calculateField( const QString & name )
{

    if ( name == "productname" ) {
        QSqlQuery query( "SELECT name FROM prices WHERE id=" +
                     field( "pricesid" )->value().toString() + ";" );
        if ( query.next() )
            return query.value( 0 );
    }
    else if ( name == "price" ) {
        QSqlQuery query( "SELECT price FROM prices WHERE id=" +
                     field( "pricesid" )->value().toString() + ";" );
        if ( query.next() )
            return query.value( 0 );
    }
    else if ( name == "cost" ) {
        QSqlQuery query( "SELECT price FROM prices WHERE id=" +
                     field( "pricesid" )->value().toString() + ";" );
        if ( query.next() )
            return QVariant( query.value( 0 ).toDouble() *
                             value( "quantity").toDouble() );
    }

    return QVariant( QString::null );
}


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

    if ( createConnections() ) {
        InvoiceItemCursor invoiceItemCursor;

        QDataTable *invoiceItemTable = new QDataTable( &invoiceItemCursor );

        app.setMainWidget( invoiceItemTable );

        invoiceItemTable->addColumn( "productname", "Product" );
        invoiceItemTable->addColumn( "price",       "Price" );
        invoiceItemTable->addColumn( "quantity",    "Quantity" );
        invoiceItemTable->addColumn( "cost",        "Cost" );
        invoiceItemTable->addColumn( "paiddate",    "Paid" );

        invoiceItemTable->refresh();
        invoiceItemTable->show();

        return app.exec();
    }

    return 1;
}


bool createConnections()
{
    // create the default database connection
    QSqlDatabase *defaultDB = QSqlDatabase::addDatabase( DB_SALES_DRIVER );
    if ( ! defaultDB ) {
        qWarning( "Failed to connect to driver" );
        return FALSE;
    }
    defaultDB->setDatabaseName( DB_SALES_DBNAME );
    defaultDB->setUserName( DB_SALES_USER );
    defaultDB->setPassword( DB_SALES_PASSWD );
    defaultDB->setHostName( DB_SALES_HOST );
    if ( ! defaultDB->open() ) {
        qWarning( "Failed to open sales database: " +
                  defaultDB->lastError().driverText() );
        qWarning( defaultDB->lastError().databaseText() );
        return FALSE;
    }

    // create a named connection to oracle
    QSqlDatabase *oracle = QSqlDatabase::addDatabase( DB_ORDERS_DRIVER, "ORACLE" );
    if ( ! oracle ) {
        qWarning( "Failed to connect to oracle driver" );
        return FALSE;
    }
    oracle->setDatabaseName( DB_ORDERS_DBNAME );
    oracle->setUserName( DB_ORDERS_USER );
    oracle->setPassword( DB_ORDERS_PASSWD );
    oracle->setHostName( DB_ORDERS_HOST );
    if ( ! oracle->open() ) {
        qWarning( "Failed to open orders database: " +
                  oracle->lastError().driverText() );
        qWarning( oracle->lastError().databaseText() );
        return FALSE;
    }

    return TRUE;
}