Keeping the connection open

[KillGabio]

Hi guys a have a very simple question.
Facts are:
I use the OCI driver to connect to my local Oracle database. Everything works fine, I can update, insert delete without any problems.

Problem is:
Everytime I exec/show a new Widget or Dialog I need to reopen my database connection, even though when I create it, the compiler tells me an old connection has been removed. I`ve tried passing the database point, mem direction (&) and creating a new class the initialices the db but nothing seems to work except opening the connection before I initialize the model. I think that the main problem is the QSqlQuery because if I use a simple QSqlquery i can pass the database as a constructor parameter. Sorry for my poor explanation.

db = QSqlDatabase::addDatabase ("QOCI");
    db.setDatabaseName("XE");
    db.setUserName("xxxxx");
    db.setPassword("xxxxxx");
    db.setHostName("127.0.0.1");
    db.setPort(1521);
    if(db.open ()){
        model = new QSqlQueryModel ();

db = QSqlDatabase::addDatabase ("QOCI");
    db.setDatabaseName("XE");
    db.setUserName("xxxxx");
    db.setPassword("xxxxxx");
    db.setHostName("127.0.0.1");
    db.setPort(1521);
    if(db.open ()){
        model = new QSqlQueryModel ();

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Thank you all in advance.

PS: Another quick question. Is there a way to call a program to execute before I open my app? Because I want to execute the oracle .bat: StartDB.bat so that the user doesn`t have to do it manually. I know that it starts when the system boots but sometimes for performance of the machine I need to close it for example....