Unsolved Warning shown in QT. Should I be worried about it? Or can I choose to ignore it?

[burrito1111]

I have added a database connection in two of my windows in QT.

login.cpp

mydb = QSqlDatabase::addDatabase("QSQLITE");
    mydb.setDatabaseName("C:/Users/burr1to/Desktop/Kaizen/Kaizen/testdb.db");
    if (!mydb.open()){
        qDebug()<<"Db problem";
    } else {
        qDebug()<< "Success";
    }

    QString username = ui->username->text();
    QString password = ui->password->text();
    QSqlQuery qry;

    if(qry.exec("select * from user where username = '"+username+"' and password = '"+password+"'")){
        int count=0;
        while(qry.next()){
            count++;
        }
        if (count==1){
            qDebug()<< "Successful login";
            qry.clear();
            mydb.close();
            hide();
            p.show();

        }
        if (count<1){
            qDebug()<< "NOT Successful login";
            qry.clear();
            mydb.close();
        }
    }

planner.cpp

    db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("C:/Users/burr1to/Desktop/Kaizen/Kaizen/testdb.db");
    if (!db.open()){
        qDebug()<< "Failed";
    } else {
        qDebug()<< "Success";

    }
    if (!db.open()){
        return;
    }
    QString what = ui->addPlan->text();

    QSqlQuery q;
    if (what == ""){
        qDebug()<< "MT";
    }
    else{
        q.prepare("insert into plan(plandet) values (:plan)");
        q.bindValue(":plan",what);
        if (q.exec()){
            qDebug()<< "Ok";
        }}



    ui->addPlan->clear();

So the 'planner' page opens after the 'login' page, and even though I have closed the database in login.cpp, a warning is shown in console.

QSqlDatabasePrivate::removeDatabase: connection 'qt_sql_default_connection' is still in use, all queries will cease to work.
QSqlDatabasePrivate::addDatabase: duplicate connection name 'qt_sql_default_connection', old connection removed.

Should I be worried about this? And what should I do to not get this error? Is the error happening because I used the same DB connection twice?

[Christian Ehrlicher]

You should worry about it.
Don't open the database more than once and then use QSqlDatabase::database() to retrieve the db connection (if you really need it)