sql/overview/subclass5/main.cpp Example File
 
/****************************************************************************
** $Id: qt/main.cpp   3.3.8   edited Jan 11 14:37 $
**
** Copyright (C) 1992-2007 Trolltech ASA.  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 );
}
QSqlRecord *InvoiceItemCursor::primeInsert()
{
    QSqlRecord *buffer = editBuffer();
    QSqlQuery query( "SELECT NEXTVAL( 'invoiceitem_seq' )" );
    if ( query.next() )
        buffer->setValue( "id", query.value( 0 ) );
    buffer->setValue( "paiddate", QDate::currentDate() );
    buffer->setValue( "quantity", 1 );
    return buffer;
}
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;
}