请问如何在qt的sqlite数据库中如何调用数据到图表，例如调用priceIn和priceOut作为数据来作为坐标数据
QSqlDatabase dbCommodity = QSqlDatabase::addDatabase("QSQLITE");
dbCommodity.setDatabaseName("../commodity.db");//建立数据库
if ( !dbCommodity.open())
{
QMessageBox::warning(this, "error", "cannot open");
}
QSqlQuery queryCommodity(dbCommodity);
queryCommodity.exec("create table wareHouse("workOrg QString,currentStore int,priceIn double,priceOut double);");
void getLineSeries(QLineSeries* series)//调用数据，这里该怎么写？
{
qreal y1, y2;
y1 =？;
y2 =？;
series->append(y1, y2)
｝
//绘制折线图
QT_CHARTS_NAMESPACE::QChart * createLineChart(QLineSeries *series)
{
QChart *chart = new QChart();
chart->setTitle("测试line图");
series->setName("测试曲线");
getLineSeries(series);//getLineSeries函数调用
QPen pen;
pen.setStyle(Qt::DotLine);
pen.setWidth(2);
pen.setColor(Qt::red);
series->setPen(pen);
chart->addSeries(series);
QValueAxis *axisX = new QValueAxis();
axisX->setRange(0, 10);
axisX->setLabelFormat("%.1f");
axisX->setTitleText("测试x坐标");
QValueAxis *axisY = new QValueAxis();
axisY->setRange(0, 100);
axisY->setLabelFormat("%.2f");
axisY->setTitleText("测试y坐标");
chart->setAxisX(axisX, series);
chart->setAxisY(axisY, series);
return chart;
}