SQL & PL/SQL

Hi all,

I've got a tricky issue:
There are two tables (almost) identically designed;
In the first one there are lets say some new data and in the 2nd one there is data to be hold & adjusted;
I built up a third table, which contains the meta informations about the two other tables (i.e. it describes the tables, so for each field of these tables, there is the field name, field type, primary key marker, etc.);

The challenge now is, how can I compare two rows (of the same primary key) field by field and get out the differences (and adjusting the target table row) using PL/SQL procedures/functions.
I thought a create a cursor over the 3rd table and call functions to get the fields out (given by the field name of the cursor), compare the two fields and return if it's equal or different...
As I've seen, there is now direct way to replace a field name in a statement - but how to resolve this with a cool workaround?
In addition, there are about 120 pairs of such tables, to be compared in the same way - so I decided to prevent creating hard coded design for the software.
Even the selection of a pair of rows from the two tables should be parameterized, 'cause the primary keys are of course different in the 120 table pairs.

Any hints or suggestions?

Thanks in advance & regards,
Peter