Comparing data in two different databases

I have two oracle databases who share database objects for example:

Table: PRICE

I am looking to come up with a efficient way of comparing the table object between the two databases. I expect them to be identical, but there can be differences as a new patch could be applied to one of the environments let's say.

I have been looking at potential solutions and I had a look at using Oracle's DBMS_COMPARISON package to compare the two database on the object:

Here is the Link

The issue I am having is that my requirement involves looking at key, values for each of the objects. For example:

Table   Key                          Compare
PRICE   Code,Type,Date,Currency      Price
USER    USER_ID                      FIRST_NAME, LAST_NAME, DOB

My question is...is there a way I can specify the key columns and specify the field to compare? Or Do I need to create temp tables and then compare the temp tables instead of the actual tables?

I'm looking to output the column where the difference is in. Appreciate if you guys can show me an example :)

Thanks in Advance