Well, optimization of SQL in general and VB/SQL (ADO.NET) apps in particular is a huge topic. There is quite a bit on MSDN if you search for it, including some information aimed directly at VB/C# ...

1. Get a subset of data from an XML file into a DataGridView, 2. Allow the user to edit said data, 3. Stick the changed data back into the XML file from where I pulled it from.