6 September 2010 at 7:45am
DataObject::get_one('SomeDataObject', 'ID = ' . $someID), DataObject::get_by_id('SomeDataObject', $someID) returns the same single DataObject.
DataObject::get('SomeDataObject', $wherestatement); returns a DataObjectSet even if there is one DataObject that matches the $wherestatement. This means that you can use alle methods from DataObjectSet like First, Last, MoreThenOnePage, Count etc. in your php code or your template file (just the notation is little different).