How schema compare work?

When uses the schema compare to compare two def files from sourceand target DBs. What things it will do in the back end side? Can I get some info for this? Thanks. The purpose of it is to see any possible wayto reduce the time consuming on 2 def files comparison. Thanks


def files?

Yes,they convert all the schemas to the def files in advance, then run the compare function.
And they want to know what it does in the internal to see if there is any steps could be eliminated to reduce the comparing time.