Why QSqlDatabase::open() returns open?

[gboelter]

I had a small problem and so, I was playing a lttle bit with the source.

Can anobody tell my, why in the following code dbMandant.open() returns true, even if there is no host, no databaseName specified??

QSqlDatabase dbMandant = QSqlDatabase::addDatabase( dbDriver, "mandant" );
 
//dbMandant.setHostName( dbHost );
//dbMandant.setDatabaseName( dbName );
dbMandant.setUserName( dbUser );
dbMandant.setPassword( dbPasswd );
//dbMandant.setPort( dbPort.toInt() );
 
qDebug() << dbMandant;
qDebug() << dbMandant.open();

QSqlDatabase dbMandant = QSqlDatabase::addDatabase( dbDriver, "mandant" );

//dbMandant.setHostName( dbHost );
//dbMandant.setDatabaseName( dbName );
dbMandant.setUserName( dbUser );
dbMandant.setPassword( dbPasswd );
//dbMandant.setPort( dbPort.toInt() );

qDebug() << dbMandant;
qDebug() << dbMandant.open();

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Here ist the output from qDebug:

QSqlDatabase(driver=""QMYSQL"", database="""", host="""", port=-1, user=""root"", open=false)
true

The manual says:
bool QSqlDatabase:pen ()
opens the database connection using the current connection values. Returns true on success; otherwise returns false.

I don't have a connection value for setDatabaseName, why open() returns true?

Regards Guenther