What is the correct way of QSqlDatabase & QSqlQuery?

Question

I got confused with the manual , should i work like this:

{
 QSqlDatabase db = QSqlDatabase::addDatabase (...);
 QSqlQuery query (db);
 query.exec (...);
}

         


        

Answer 1

I find that the instructions have to be run exactly in the order it is below or else you have issues, either with the database connection or query. This works in Qt5.

QSqlQueryModel *model = new QSqlQueryModel;
db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(fileName);

if (db.isValid())
{
    db.open();
    if (db.isOpen())
    {
        QSqlQuery searchQuery(db);
        searchQuery.prepare("SELECT * FROM myTable");
        searchQuery.exec();
        if(searchQuery.isActive())
        {
            model->setQuery(searchQuery);
            sui->DBDisplay->setModel(model);
            db.close();
        } else {
            qDebug() << "query is not active";
        }
    } else {
        qDebug() << "DB is not open";
    }
} else {
    qDebug() << "DB is not valid";
}