16. A database query system according to claim 14 wherein said QAUI displays said nonselectable sets and visually differentiates said selectable sets from said nonselectable sets.
16. A database query system according to claim 14 wherein said QAUI displays said nonselectable sets and visually differentiates said selectable sets from said nonselectable sets. 17. A database query system according to claim 16 wherein said QAUI visually differentiates said sets by color.