MDB::setOptions & singleton

Hello everyone, I have 2 questions about MDB 1) Is this the right way to use the MDB::setOptions method? It seems to work... $this->connection = MDB::connect($dsn); MDB::setOptions($this->connection, array('optimize'=>'portability')) ; Is this set once forever Or do I need to set the option every time I instanciate a new connection? 2) what exactly is the benefit of using the sigleton method? Is this working between classes? My root class instanciates a MDB object, and all children classes do a connection to any of 3 databases. Can I reuse the connections accross classes? What happen if I call a close() in one class? Thank you Vincent