10. The method of claim 2, wherein the child box has a parent box that comprises a first decorrelation output box, said first decorrelation output box having a parent that comprises a first correlation input box, said first decorrelation output box including a first quantifier ranging over a magic child box associated with the child box, said first decorrelation output box also including a first natural join predicate, wherein the magic box comprises a source of the correlation bindings, and wherein the NMQ absorb process comprises the steps of: identifying each child box of the child box, referred to as a grandchild box; determining whether any of identified correlated grandchild boxes can be decorrelated; performing a feed process to each grandchild box by performing steps comprising: providing a decorrelated view of the grandchild box to the child .box, said decorrelated view including: a decorrelation box interposed between the child box and the grandchild box, wherein said decorrelation box comprises a second decorrelation output box if the grandchild box can be decorrelated, or a decorrelation input box if the grandchild box cannot be decorrelated, wherein said decorrelation box includes a second quantifier ranging over a magic box associated with the grandchild box to carry the correlation bindings; said decorrelated view also including a second correlation input box to partition bindings provided by the decorrelation box to the current box, said second correlation input box including a second correlation predicate whose correlation source is the decorrelation box; and modifying the correlated descendant box to receive the correlation bindings from the second quantifier instead of the original source; eliminating the natural join predicate of the first decorrelation output box; eliminating the second correlation predicate; providing an output of the correlation bindings in the second correlation input box by adding an extra column in the second correlation input box; and providing an output of the correlation bindings in the child box by adding at least one additional column in the child box.
10. The method of claim 2, wherein the child box has a parent box that comprises a first decorrelation output box, said first decorrelation output box having a parent that comprises a first correlation input box, said first decorrelation output box including a first quantifier ranging over a magic child box associated with the child box, said first decorrelation output box also including a first natural join predicate, wherein the magic box comprises a source of the correlation bindings, and wherein the NMQ absorb process comprises the steps of: identifying each child box of the child box, referred to as a grandchild box; determining whether any of identified correlated grandchild boxes can be decorrelated; performing a feed process to each grandchild box by performing steps comprising: providing a decorrelated view of the grandchild box to the child .box, said decorrelated view including: a decorrelation box interposed between the child box and the grandchild box, wherein said decorrelation box comprises a second decorrelation output box if the grandchild box can be decorrelated, or a decorrelation input box if the grandchild box cannot be decorrelated, wherein said decorrelation box includes a second quantifier ranging over a magic box associated with the grandchild box to carry the correlation bindings; said decorrelated view also including a second correlation input box to partition bindings provided by the decorrelation box to the current box, said second correlation input box including a second correlation predicate whose correlation source is the decorrelation box; and modifying the correlated descendant box to receive the correlation bindings from the second quantifier instead of the original source; eliminating the natural join predicate of the first decorrelation output box; eliminating the second correlation predicate; providing an output of the correlation bindings in the second correlation input box by adding an extra column in the second correlation input box; and providing an output of the correlation bindings in the child box by adding at least one additional column in the child box. 11. The method of claim 10, further comprising eliminating the first decorrelation output box.