drill-down
Reports which display all their data at once may not
be convenient to use. With drill-down you can display an overview of the data
but give users the ability to reveal further layers of data as required. For
example, one user may be interested in seeing sales of a particular product
group or individual product in all years. Another may be interested in seeing
sales of all products in a particular quarter or month. Each user can
drill-down through the products or years to see only the data they require. You
drill-down by expanding and collapsing the tree structures of the lists
containing the data.