I did some initial schema analysis on Oracle Apps R12 sample database, VIS.
VIS uses hardly any primary keys, many non unique indexes, and a LOT of package and triggers.
Lots of potential for data integrity and tuning issues.
Here is an Oracle script to find the tables that don’t have any foreign keys.
Tables that are neither a parent table, or a child table.
After discovering so many tables that no primary key, at so many shops, I finally wrote an Oracle script to list all the tables that did not have a PK.