9. The method of claim 7 , wherein, a second comparison of the set of comparisons is based on a second merge attribute as selected by the requesting system, wherein the second merge attribute is different from the merge attribute and is associated with the elements of the first XML document and the second XML document being compared in the second comparison, and wherein the second merge attribute is defined to be of type xml:ID in the schema.
7. The method of claim 1 , further comprising: parsing the first XML document and second XML document to generate the list of attributes; sending the list of attributes to a requesting system; and receiving from the requesting system the merge attribute selected from the list of attributes.