>Do you usually close the connection? And if yes, how? The last segment of your code shows that you call Fill() method to fill the dataset. But this, if I understand correctly, leaves the connection open. How do you deal with this?

This should open and close the connection automatically. This is one reason Using/End Using was used. One advantage, as earlier mentioned, is that if something goes wrong in that code, it will be closed automatically as well as it is encapsulated in the Using/End Using. But, in this thread, I believe Viv mentioned something about the data adapter which might add additional variables to this context.