removing database

What is wrong with this code. Why I get warning about it?
WARNING: QSqlDatabasePrivate::removeDatabase: connection 'qt_sql_default_connection' is still in use, all queries will cease to work.

Code:

---

{
QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
    db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb)};FIL={MSAccess};DBQ=E:file.name" );
    qDebug() << "DRIVERS :" << QSqlDatabase::drivers();
 
    if (!db.open()) {
       qDebug()<< db.lastError().text();
       return false;
     }
}
 
if(QSqlDatabase::database().isOpen()) {
        qDebug() << "db name :" << QSqlDatabase::database().connectionName();
        QSqlDatabase::database().close();
        QSqlDatabase::removeDatabase(QSqlDatabase::database().connectionName());
    }

---

Should I leave this warning as it is?
Because I need to close connection and open new one to another database.

Do you have any QSqlQuery objects alive when you try to remove the connection? If you have, then that would cause the warning.

Yep, you probably have a QSqlQuery object that hasn't passed out of scope and hasn't been clear()ed.