I've to apologize up front because I think I've something missed in the Documentation regarding dbms_redact setup, or restrictions therewith.
If so I'm sorry for wasting your time just to point me in right direction.
I've a simple test-case on livesql (but you cannot run it there, because you have no execute-right on dbms_redact), please have a look at: https://livesql.oracle.com/apex/livesql/s/kcq634fgexodc6m6a8n4esb0l
My questions is regarding the ORA-28094 raised by the "tom_redact_view_28094"-View (at statement 13).
The restriction I couldn't find, and to be honest don't understand, is:
The above mentioned view just selects all columns from the base-table (which has one redacted column - ssn), and just add two columns together (nr1 + nr2). And this addition seems to be enough to raise the ORA-28094.
If you do not select the "sum" column from this view, it works just fine.
I've tested this on AIX and Oracle 19.5, and on Oracle 12.2 and 18.3 on Oracle-Linux.
All of the above shows the same behaviour, which is another reason why I think I've just missed a restriction in the documentation.
I know I could redact the column in the view, but I think this would defeat the purpose. Because I would like to redact the 'base-table' and rather not 10 views based on this table.
In the end my tests would go a step further, because my initial setup started with dbms_tsdp_* using dbms_redact. But I think that dbms_redact is the restricting part, so I've simplified this test-case.
I hope the test-case and my explanation is sufficient for you to reproduce the behaviour.
And as stated above if I've missed something in the documentation, and you can point me in the right direction, I'm grateful and sorry!
Thank you in advance for your time and help!