If you are trying to compare  two files, utilities like
diff are available to do that. That is if you want to
get a readout of where the files  are different (data,
whitespaces etc.)

If you want to know if the table structure has
changed, I guess this will be reflected as the nodes
in the XML. In this case, you have to use an XML
parser to do the trick. I think DOM parser (xerces)
should do for this purpose.