Question

How can I know if a SELECT access an invalid position? e.g position 651 is a not valid position in my data base but my code does not show an error:

query.prepare("SELECT creationDate, state FROM jobs WHERE jobId = '" + QString::number(651) + "'");
error = query.lastError().text();
if (query.exec())
{
   query.first();
   qDebug() << query.value(0).toString();
   qDebug() << query.value(1).toString();
}
else
    qDebug() << error;

Thank you very much.

Answer 1

You have to check if first() is true.

if (query.exec())
{
   if (query.first())
    {
       qDebug() << query.value(0).toString();
       qDebug() << query.value(1).toString();
    }
    else
    {
       qDebug() << "error";
    }
}

http://doc.qt.io/qt-5/qsqlquery.html#first