5. The method as claimed in claim 4, wherein said steps of converting generate another linked data structure including a third node defining said first un-nested query and a fourth node defining said second un-nested query.
6. The method as claimed in claim 5, wherein said another linked data structure includes a series of nodes defining a sequence of join and outer-join operations including a consecutive series of m joins, and wherein the first i joins are evaluated at a time first for i=1, then for i=2, then for i=3, . . . , and finally for i=m.