Connect to database

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I need to connect to a postgree database 'testeDB' on my localhost

I tried the following code:

QSqlDatabase DB = (QSqlDatabase::addDatabase(QObject::tr("QODBC")));
    if ( &DB ) {
        DB.setDatabaseName( QObject::tr("testeDB"));
        DB.setUserName( QObject::tr("testUser") );
        DB.setPassword( QObject::tr("test") );
        DB.setHostName( QObject::tr("localhost"));
 
        if ( DB.open() ) {
            qDebug()<< "OK!";
        } else {
            qDebug()<< DB.lastError().text() << "\n";
        }
    }

QSqlDatabase DB = (QSqlDatabase::addDatabase(QObject::tr("QODBC")));
    if ( &DB ) {
        DB.setDatabaseName( QObject::tr("testeDB"));
        DB.setUserName( QObject::tr("testUser") );
        DB.setPassword( QObject::tr("test") );
        DB.setHostName( QObject::tr("localhost"));

        if ( DB.open() ) {
            qDebug()<< "OK!";
        } else {
            qDebug()<< DB.lastError().text() << "\n";
        }
    }

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but I get an error when trying to open the connection, saying: (I`m translating it, so it may not be too accurate)
"Data Source name not found and QOBC3 default driver not specified: Not possible to connect."

Sooooo: how does I fix this?