7. The method of claim 2, wherein the child box has a parent box that comprises a decorrelation output box, said decorrelation output box having a parent box that comprises a correlation input box, said decorrelation output box including a first quantifier ranging over a magic child box associated with the child box, wherein the magic child box comprises a source of the correlation bindings, and wherein the AMQ absorb process comprises the steps of: routing the correlation bindings from the magic child box to the child box and creating an output column in the child box to provide an output of the correlation bindings; substituting the first quantifier in place of the decorrelation output box as the source of the correlated descendant box's correlation bindings; and deleting natural join predicates from the decorrelation output box and the first quantifier.
7. The method of claim 2, wherein the child box has a parent box that comprises a decorrelation output box, said decorrelation output box having a parent box that comprises a correlation input box, said decorrelation output box including a first quantifier ranging over a magic child box associated with the child box, wherein the magic child box comprises a source of the correlation bindings, and wherein the AMQ absorb process comprises the steps of: routing the correlation bindings from the magic child box to the child box and creating an output column in the child box to provide an output of the correlation bindings; substituting the first quantifier in place of the decorrelation output box as the source of the correlated descendant box's correlation bindings; and deleting natural join predicates from the decorrelation output box and the first quantifier. 9. The method of claim 7, further comprising the steps of: determining whether the correlation input box and the current box can be merged, and if so, performing said merging.