🚀 go-pugleaf

Hi, i'm italian, excuse me for my poor english.
I use JBX and 2005 and MySQL 4.1 with InnoDB, my application works fine.
Now i should want to use transactions, but, if i use:
QueryProvider qProv = new QueryProvider();
   ParameterRow num = new ParameterRow();
   Column param = new Column();
   num.setColumns(new Column[] {param});
   param.setColumnName("ID");
   param.setDataType(com.borland.dx.dataset.Variant.INT);
   param.setParameterType(ParameterType.IN);
   num.setInt("ID",3);
   String qry = new String("Update country SET countryname='USA2' WHERE
ID= :ID ");
   qProv.executeStatement(db2,qry,num);
   db2.commit();
   //or
   //db2.rollback();
It work fine, while if i use QueryDataSet and edit a JdbTable or
some field of a form, and then in an Jbutton_actionPerformed:
qds.saveChanges(qds);
db2.rollback();

rollback() NOT WORK!!!

What'is the code that i have to use for work???

In JbInit() i have:
db2.setTransactionIsolation(java.sql.Connection.
                                TRANSACTION_READ_UNCOMMITTED);
    db2.setUseTransactions(true);
    db2.setAutoCommit(false);
    db2.start();

Thanks, regards
Salvo, Nessina, Italy